The Great American Eclipse – 40 days to go

July 12th, 2017 by Roy W. Spencer, Ph. D.

The March 29, 2006 total solar eclipse, composite photo taken from images gathered by 3 separate Canon 5D cameras ranging from 8 sec to 1/1000 sec exposure time (Miloslav Druckmller, Peter Aniol, click image for full-resolution).

The Great American Eclipse of Monday, August 21, 2017 will be one of only a couple of chances for many Americans to experience a total solar eclipse. This is the first coast-to-coast total eclipse since 1918. The last total eclipse visible from any point in the contiguous U.S. was 38 years ago, in 1979. Your next chance will be April 8, 2024.

A total solar eclipse at mid-day will be amazing. If you are in the path of totality, some of the brighter stars and planets will appear. The temperature can fall rapidly.

The following map, provided by, has a wealth of information regarding how much of the sun will be covered, at what time, and how long totality will last:

Eclipse details for the 21 August 2017 total solar eclipse, click image for full-resolution.

While a partial eclipse will be experienced everywhere in the U.S., where you will want to be is in the narrow (~70 mile wide) path of “totality”, there the moon completely covers the sun. If the skies are partly clear, some of the brighter stars will appear as well as a couple of planets. Totality will last for as long as 2 minutes and 40 seconds.

As long as you are within about 25 miles of the center of the path, you will experience the better part of that maximum time of totality. So (for example), even though Nashville, TN will be 25 miles from the centerline, it will still experience 2 minutes of total solar eclipse.

Safety First!

Since the August 21 eclipse will occur when the sun is high in the sky, it WILL NOT BE SAFE to view it with the naked eyes at any time until totality occurs (the moon completely covers the sun). Until that time, you will need a pair of solar viewing glasses, which are MUCH darker than sunglasses. Do NOT attempt to view the sun with sunglasses, you will permanently damage your eyes. Just before totality, there will be a tiny sliver of bright sunlight…do NOT be tempted to look at it. Solar viewing glasses (and even solar viewing binoculars) might well sell out early, so get them soon.

Will It Be Cloudy?

Climatologically, certain parts of the country will have a greater chance of seeing the eclipse than others. has those probabilities.

But, as a meteorologist I can tell you that weather — not climate — will determine whether you have mostly clear skies or are under a thick thunderstorm anvil.

The following MODIS satellite imagery for mid-day on 21 August 2015 shows that your success will depend heavily upon just what kind of weather systems are occurring and where.

MODIS satellite imagery on 21 August 2015, with the 2017 eclipse path of totality superimposed, showing the wide range of cloud conditions that can occur during a summer eclipse in the United States.

It could be that one of the climatologically best locations (say, north-central Oregon) will be completely cloud covered (as it was on 21 August 2015), while one of the worst places (the Smokey Mountains) will have mostly clear skies if a cool front recently passed by. There is no way to know more than a few days in advance. Thunderstorm anvils blowing off large thunderstorm complexes will likely ruin the experience for many people. This is why I won’t decide where I will go until 1-2 days before the eclipse. I’d love to be in Teton Village for the event, but not if it’s cloudy.

Here in the southeast U.S. in August, even a mostly sunny day will have “popcorn” cumulus clouds that develop by mid-day. One option I’m considering (if that’s the weather forecast) is to go to one of the large reservoirs which tend to stay clear under such condtions, for example Kentucky Lake east of Paducah, or Watts Bar Lake in eastern Tennessee.

But even if you are stuck under the clouds, it is still worth experiencing being in the path of totality. It’s going to get really, really dark in the middle of the day.

To Travel or Not to Travel?

If you live farther than about 6 hours away from the path of totality, and can’t drive there the morning of the eclipse, your other option is to get within 100-200 miles of the path of totality and stay in a hotel the night before, then drive the rest of the way in the morning. Hotels in the path of totality have all been sold out for about a year or so.

I was originally considering going to downtown Nashville, but I’ve heard that hundreds of thousands of people might converge on some of the metro areas, and there could be gridlock. So, I’m still conflicted about whether to go metro or rural.

How to Record the Event?

For most people, just experiencing the event will be magical. Being with a large group of people will raise the excitement level (although if you are easily annoyed by a few overly-excited voices, you might want to avoid crowds).

Now that most people have smartphones, taking some video of the event will be the easiest way to capture the moment. There will be lots of great photos of the sun itself after the event, and they will all look about the same. So, capture the scenery and the reactions of people in cell phone video, instead.

For those of us with heavy-duty photo equipment, we have a number of choices, none of which are easy. Video or stills? If video, real-time or time lapse? Wide-angle landscape shots or zoom in on the sun (with solar filters if not during totality)? I haven’t decided yet. I will probably have one camera on a tripod doing wide-angle video with the sun near the top of the frame, and another camera with a 200-300mm focal length lens taking bracketed exposures of the solar corona over the ~2 minutes of totality, which is what went into the spectacular composite photo at the start of this article.

No matter where we choose to go, happy eclipse hunting, everyone…lets hope for blue skies for as many people as possible!

2017 Eclipse Websites

53 Responses to “The Great American Eclipse – 40 days to go”

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  1. Lynn Clark says:

    Rocket Scientist Destin of Smarter Every Day did several useful videos about the upcoming eclipse:

    Extended discussion on his second channel:

    How to video the eclipse:

  2. Massimo PORZIO says:

    Hi Dr. Spencer,

    On August 11 1999, me and some friends of mine went to Baden Baden in NW Germany to watch the last total eclipse of the century.
    There was the best place to get the full Sun covered for us.
    I remember that it should had be about 11 AM, and it has been an awesome experience. In few seconds (less than a minute) the night came accompanied by a light wind, and after few minutes the day returned back. Impressive.
    Looking to the map, I suggest you to move just few miles north that day.
    It worth the trip.

    Have a great day.


    • Massimo PORZIO says:

      BTW, just to tell you the curious event, that day at Baden Baden the weather was cloudy, but the eclipse induced wind cleaned the sky while it happened.

      • David Appell says:

        How quickly did the wind come up? An hour before totality? Minutes?

        • Massimo PORZIO says:

          Hi David,
          It came up just a little after (few seconds) that the light started to dim down considerably.
          In fact we were all frustrated because of the completely cloudy sky, till that moment.
          I don’t know if that was just a case or it’s the normality in that event, but in few seconds the clouds between us and the eclipsed sun dissolved away, leaving us the opportunity to see the full dish obscured by the Moon and the following return of the full light in the successive few minutes.
          Very impressive it has been the way the shadows quickly formed on the things around and suddenly disappeared when the solar dish was fully obscured.

          Despite I was well aware of what it was the running event, for a little moment I felt worried of what I was experiencing.

          We were precisely here:
          If you zoom out, the parking lot at E/SE wasn’t there those days, it was all countryside.
          I remember that I asked to my fellows to shut up their mouths to listen the impressive silence around. No birds chirping, no dogs barking, nothing at all. Neither the cars on the highway were running, an absolute silence.

          That time I realized why ancient crowds worship the sun and the moon!

          Have a great day.


  3. Norman says:

    The weather will play a big role where I plan to watch. I am an hour away from Lincoln, NE just wonder what the traffic will be like. A little South and you get the full 2 minute effect.

    Clear skies for that day across the US would be great!

  4. ossqss says:

    Thanks for the reminder Doc. Great excuse for road trip to SC or N Georgia from these shoes.

  5. John F. Hultquist says:

    Many year ago (1970 or ’71 ?) we went with a class from Georgia State University. Overnight in Waycross and then spent the day in the Okefenokee Swamp.
    The idea was to see how the animals responded.

    So I suggest you go to a nature preserve.

    Nice post with good info — thanks Roy.


  6. g*e*r*a*n says:

    I was planning on using my welding goggles to watch, but fortunately I did some research first. Welding goggles have a “shade” rating. Mine are shade 9. It is recommended that you use shade 14, of higher, to look at the Sun.

    There are some on-line sources for eclipse-viewing glasses that are very cheap, made of cardboard. They advertise “ISO” certified.

    Has anyone ever used these cheaper glasses?

    • Gordon Robertson says:

      g*r…”There are some on-line sources for eclipse-viewing glasses that are very cheap, made of cardboard.”

      Are those the ones with the pinholes. Likely burn tiny holes in your retinas.

  7. Tim Rhyne says:

    Roy, my brother has a place between Riceville and Decatur, Tennessee. If you are interested in visiting for the event please contact me.

  8. Svante says:

    Pardon me for changing the subject.

    Mike Flynn came up with a splendid analogy comparing wood and CO2:

    It is common for bridges and jetties to keep the water underneath ice free:

    – The situation can persist for days and weeks.
    – There is not much downward conduction through air.
    – Convection is not prevented, and does not work downward.
    – The snow on top shows that there is little from above.
    – The wood does not have a lot of mass.
    – Is this not an example of back-radiation?

    Some energy is carried up by convection, but the same is true for the atmosphere.

    What other problems can you see with this analogy?

  9. jimc says:

    “By recording changes in the radio signal, these citizen scientists will collect data on the ionosphere”

    “Though all 150 receiver kits created with a National Science Foundation grant have been claimed, it is not too late to join the EclipseMob, Nelson said. The project’s website includes instructions for ordering parts and constructing your own radio receiver.”

  10. Gordon Robertson says:

    I wonder if we’ll be able to see it in the Canadian part of America? Or is it only in the United Sates of America part of America?

    • jimc says:

      Where’s Canada? 🙂

      • Gordon Robertson says:

        jimc…”Wheres Canada?”

        It’s in America. ☺

      • Gordon Robertson says:

        jimc…”Wheres Canada?”

        Got your humour, I was visiting Scotland a couple of years ago, having been born there. I was checking out of a department store and the cashier, a very nice Scottish lady, asked where I was from. I told her Canada (actually, I’m Scottish by DNA). She looked surprised and told me she thought I was American.

        I told her I am American. She looked at me as if I was daft (a good, old Scottish word) and asked how I could be both Canadian and American. Keeping a straight face, I told her, “…because Canada is in America”. Then I awaited a response.

        She looked at me for a second then the light went on. “Oh, she claimed, I never thought of that, Canada ‘is’ in America”. She assured me she won’t forget that, for which I thanked her.

        In the UK, in particular, people tend to think of the United States as America with countries like Canada and Mexico being located outside America. Even here in Canada we’re that daft, we refer to the United States as America while we are sitting right in America here in Canada.

        About this article and the sun. Most people, I dare say, actually think the Sun does rise in the east and travel across the sky. It’s called an illusion and it’s due to relative motion. When you get used to it, it’s just as easy to visualize the horizon dipping below the Sun in the morning and rising above it in the evening. That practice grounds you, gets you in better touch with reality.

        By the same token, it’s just as easy to see that the US is not America, it’s in America. I am not holding my breath that such an illusion will disappear anytime soon.

        It’s akin to calling the UK ‘England’ a thing you’d regret saying in some parts of Glasgow, Belfast, or Cardiff. Them thars fightin’ words.

        Re the Scottish word ‘daft’ which means stupid or crazy. The great Scottish mathematician/physicist Maxwell, essentially a genius who was highly regarded by the likes of Einstein, was named Daftie Maxwell by his schoolmates. What was it Rodney Dangerfield used to say about respect?

        • Smoking Frog says:

          No, it’s equivalent to calling England “the UK.”

          The idea that there’s something wrong with calling the United States “America” is pretty silly. The other countries in the Americans are proud of their names; e.g., Mexicans like the name “Mexico.”

          They have three names for Americans: americanos, norteamericanos, estadounidenses (“unitedstatesians,” so to speak). The last one is the least common.

    • Roy Spencer says:

      yeah, yeah. I left Canuckistan out because it will be cloudy there till 2047, anyway.

      • Gordon Robertson says:

        Roy…”yeah, yeah. I left Canuckistan out because it will be cloudy there till 2047, anyway”.

        Don’t make us come down there and kick your butts again like we did in 1812. ☺

        We could use some cloud in Vancouver right now. There’s a bit around but it’s hotter than a monkey’s butt.

        It likely won’t be named Canada long anyway, they have already renamed Vancouver to Hongcouver. If they rename Canada I’ll enter your Canuckstan offering. It would likely be a better name when traveling through Russia if they ask where your from.

        Not that I plan to be traveling through Russian anytime soon but if the Democrats don’t get off this stupid Russian baiting they may be over here, or what’s left of it.

    • David Appell says:

      Only the US. Here’s the path of totality:

  11. Svend Ferdinandsen says:

    I will be somewhere in Woming at the time, and hope to see the eclipse.
    I was in Hungaria in 1999, but missed the most of it just trying to make some pictures.
    Now i will let others do the photographing and just enjoy it.

  12. David Appell says:

    I’m right under the path of totality, and have been looking forward to this for a few years. In Oregon August days are almost always sunny and clear, so it should be a good show. I expect it will shut down most of the state, traffic-wise.

    • Gordon Robertson says:

      DA…”In Oregon August days are almost always sunny and clear…”

      Holy smoke, you’re just down the road from Vancouver. We should get together over a beer and have a good, rousing argument (er…debate).

  13. David Appell says:

    Roy wrote:
    “Hotels in the path of totality have all been sold out for about a year or so”

    Here in Oregon, some hotels *cancelled* these long-held reservations, in order to jack their prices up to as much as $1000/night.

  14. AaronS says:

    Is there a difference during a low and high phase of solar activity? Would be interesting to compare.

  15. David Appell says:

    Roy wrote:
    “If you live farther than about 6 hours away from the path of totality, and cant drive there the morning of the eclipse….”

    I wouldn’t count on this in Oregon. The north-south highway here, I-5 from Portland to Eugene, is going to be jammed. Probably, literally, jammed. My sister and her family are coming down to my place the day before. The highway will probably also be jammed for hours afterward.

  16. ren says:

    “The trillion-ton piece of ice just broke off from the Larsen-C ice shelf on the Antarctic peninsula. It totals about 2,240 square miles about the size of the state of Delaware and its volume, 40 trillion cubic feet of ice, is twice that of Lake Erie, reports Project Midas, a UK-based science group dedicated to studying the ice shelf.”

  17. John of Cloverdale, WA, Australia says:

    My sadly departed Mum (she reached 103 years old) was born in May 1900, when the Halley’s Comet came closest to Earth. The newspapers of that time were predicting the end of the world.

  18. Steve Richards says:

    My wife thoughtfully booked two tickets to a ferry crossing the English Channel a few years back. She did it over 18 months in advance. It was billed as a ‘total eclipse voyage’.

    It was really good. On the day, the media were full of it and people were asking ‘how do you get tickets’ = book early 🙂

    When the time arrived, we were mid channel, we turned to follow the eclipse.

    You could see the shadow on the sea surface racing towards us.

    Darkness fell, sea birds got spooked.

    It looked like the sea flattened but I suspect it was just the low light level causing an illusion.

    We had a couple of minutes of totality, the sun emerged, we turned and went back to port.

    Well worth it.

    I would advise getting out onto some level ground so you can see the ‘terminator’ race towards you.

  19. Richard Barraclough says:

    I made the effort to go from Johannesburg to southern Botswana in 2002 for an eclipse. In contrast to your fears of grid-locked roads, there were no more than a handful of people at our hill-top vantage point.

    We climbed a modest hill of a couple of hundred metres, and were able to see clearly the terminator shadow racing towards us across the flat terrain at several hundred kilometres per hour. That has stuck more in my mind than the totality. It also struck me that at 99 per cent total, it is still quite light, but 100 per cent is almost like night.

    • Massimo PORZIO says:

      Hi Richard.
      “It also struck me that at 99 per cent total, it is still quite light, but 100 per cent is almost like night.”
      It struck me too, I was expecting a more smooth fade away of light instead.

      About the traffic issue, in Germany we experienced about 100km of queue on highway 5 during our comeback to home.
      The day later the newspapers wrote about a queue of 350km, I can’t testify they were all those, but 100km for sure.

      Have a great day.


  20. Emeritus says:

    Dr. Spencer, there are a few, at least on a Norwegian climate blogg, that is flabbergasted that You did mot answer OlofR’s question regarding NOAA 14 and 15.

  21. Bryan says:

    I’ll be watching at the Hermitage. It’s free, the first 2,000 people can receive a pair of viewing glasses, and for all those attending entry to the Hermitage is $17 instead of $20.

  22. Smoking Frog says:

    I was in a near total eclipse on a beach in Cape Cod in the late 1960s. A german shepherd standing near me whimpered and put his face in the sand.

    A flock of birds took off from one side of the bay to fly to their sleeping place on the other side, then, when the darkening reversed, squawked, turned around, and flew back.

  23. Massimo PORZIO says:

    Hi Dr. Spencer,
    since you are one of those climatologist who love performing backyards experiments, Ive just a thought about making the eclipse day more interesting for you.
    I think that the following could be a good idea to trying an experiment that day.
    Since one of the worries of the AGW alarmists is the possibility to overcome a stability tipping point of the system, the total eclipse could be a good circumstance to try what we in electronics call an impulse response analysis of it.
    As evidenced by Richard Barraclough above and confirmed by myself, the event is quite impressive for the speed at which the solar radiation drops and then returns back in few seconds.
    This could be a good stimulus signal to establish if there are those positive feedbacks and how much they are dominant or not over the negative ones.
    If I was you, I would plan to carry a data logger with some high speed thermometers and a radiometer in the Vis/NIR band to correlate the measurements.
    I would use thermocouple high speed thermometers for the surface measurement and for air few meters above the surface (it doesnt matter their absolute precision, since this is a qualitative temperature measurement not a quantitative one).
    If the temperature measurements presented meaningful overshoots then we could be close to an instability point, that is the positive feedbacks are dominant, otherwise they aren’t.
    Of course the measurements are local so nothing of global, but I think that they could give a good qualitative answer about how much we are close to a possible tipping point.
    Have a great weekend.


  24. Brian D says:

    Here is the link to the Feb 26, 1979 eclipse.

    I remember being in school, and we took a piece of paper and poked a hole in it, faced it toward the Sun through the window. The shadow of the moon could be seen on the sheet of paper we laid down on the window ledge as it was moving across the face of the Sun. Here in N MN, it was around 90% totality then.

    Looks like 80% around here this time around. A welder’s mask or goggles should work well, too, to view this one.

    It will be interesting to see how the weather is affected, as this will be a mid-day eclipse (starting 9am (W), ending 4pm (E)). With all the web cams around now, we should be able to catch the effects, if any, along with weather observations.

    April 24, 2024 eclipse. Looks like 75% here in N MN.

  25. RBrown says:

    Dr. Spencer,
    I live in Nashville, TN and have been an avid reader of your blog since the ClimateGate days. I would be honored to host you or members of your team for the eclipse. With our youngest heading to college mid August, we have plenty of extra rooms. I would consider your stay a small way of repayment for the countless hours I have spent on your blog over the years.
    Sincerely, RBrown

  26. RBrown says:

    Also as an FYI, Nashville hosted 240,000 downtown for the largest fireworks display in the US.
    This past July 4th. The convergence on 3 interstates makes for easy access. Of course it doesn’t hurt knowing the best side streets. I suspect Nashville will make it a party and provide some great music and entertainment while waiting for the event.

  27. D MacKenzie says:

    Dr. Roy, it seems to me this eclipse is a prime opportunity for one of your famed “experiments”. Maybe readings from pyrgeometers at weather stations along the route can infer some interesting data about “back-radiation” based on the rate of radiation decline as radiation from the sun is “turned off”…or comparing that to decrease at ground level as the sun goes behind a cloud….

  28. Eric Swanson says:

    The path of the eclipse will give maximum tidal forcing over Carbondale, MO. That geological region is the area of the New Madrid, MO fault, which produced one of the largest recorded earthquakes in US history.

    Given that there is some correlation between quakes and the monthly eclipses and full moons, I would not want to be anywhere near the area on 20 August. Your experience may vary…

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