Weather & Climate

Eclipse Weather Prospects

Where's the best place to go to see the total eclipse of the Sun on August 21, 2017? There's no single right answer. Within the constraints of available time and money, experienced eclipse chasers will aim to strike a balance among three factors:

  1. Duration of totality — There's so much to see during a total solar eclipse that every second counts. The longer the Moon completely covers the Sun, the more your eyes will get used to the dark and the more of the Sun's faint outer corona you'll see. You'll also have more time to look for stars and planets, to enjoy the sunrise/sunset colors around the horizon, and — if you're so inclined — to shoot pictures. Totality lasts longer toward the center of the path of the Moon's shadow than it does near the edge, and it lasts longer in southern Illinois than it does to the northwest or southeast.
  2. Local accommodations, amenities, and attractions — The ideal observing site is accessible, safe, and secure with convenient food, water, and restrooms. But there are other things to think about too. Do you want to experience the eclipse in relative seclusion or in a big crowd? Do you want to take a short trip just to see the eclipse, or do you plan to make a vacation of it and spend extra time sightseeing in the area? With the path of totality spanning the U.S. from coast to coast, your options run the gamut from big cities to small towns and from national parks to neighborhood playgrounds.
  3. Likelihood of clear skies — No matter how close you are to the center of the path or the point of maximum duration, you won't experience the many splendors of totality if it's cloudy or raining. If you have the flexibilty to travel, it makes sense to aim for a spot where you're likely to have a clear sky based on historical data. But just as stock-market investors say, "Past performance is no guarantee of future results," eclipse chasers say, "Climate is what you expect; weather is what you get." So keep your eye on the weather forecast in the days leading up to the eclipse, and have a Plan B in case you need it.

There are many sources of excellent maps that show where totality happens and how long it lasts at various locations. And there are many travel opportunities to excellent observing sites offered by tour companies and communities along the path of totality. But how do you figure the likelihood of clear skies at any point within the path of totality, especially months or weeks in advance? You ask Jay Anderson, a Canadian meteorologist and eclipse chaser who has been the "go-to guy" for eclipse climatology and weather forecasting for the past several decades, just as his colleague and co-author Fred Espenak has been the "go-to guy" for eclipse path predictions; their latest book together, Eclipse Bulletin: Total Solar Eclipse of 2017 August 21, is listed on our Books & Articles page.

Fortunately you don't have to know Jay Anderson personally to get his advice on where to find clear skies on Eclipse Day. He and his colleague Jennifer West maintain a website that all experienced eclipse chasers have bookmarked. Thank you, Jay, for the remarkable service you have been providing to eclipse chasers for so long!

Eclipsophile: Climatology and Weather for Celestial Events — Total Solar Eclipse of August 21, 2017 (Jay Anderson & Jennifer West)

Now that the August 21st eclipse is almost upon us, Jay and Jennifer have added links where you can find up-to-the-minute weather predictions:

Eclipsophile Weather Desk 2017

For another perspective on weather prospects for the eclipse based on a different kind of analysis, check out astronomer Kevin Gullikson's blog, "Adventures of the Datastronomer." And for a different approach to displaying the likelihood of clear skies on eclipse day, see the following resources from the National Centers for Environmental Information (NCEI) at the National Oceanic and Atmospheric Administration (NOAO), the Cooperative Institute for Climate and Satellites at North Carolina State University (CICS.NC), and the North Carolina Institute for Climate Studies (NCICS):

For stargazing weather forecasts more generally, check out the Clear Sky Charts produced by Canadian amateur astronomer and software architect Attilla Danko. These offer detailed 48-hour predictions for cloud cover, transparency (clarity of the air), and "seeing" (steadiness of the air) for any location on the planet. Of particular interest, beginning on August 19, 2017, is the following:

Clear Sky Charts Along the 2017 Eclipse Path (Attilla Danko)

There are many sites on the internet that will show you the current weather at any location on Earth along with a short-term (usually 5- to 10-day) forecast. Among them:

These will become more useful as we get closer to the eclipse. Here's another site that isn't on most people's radar (pardon the pun) but that could be especially valuable in the days leading up to August 21st, thanks mainly to its stunning data visualizations. It was developed in the Czech Republic:

Ventusky (InMeteo, Marek Mojzík & Martin Prantl)