A combination photograph shows the beginning to the end, top left to bottom right, of a total solar eclipse as seen from the beach on the island of Ternate, Indonesia, on March 9, 2016. (Reuters)

The total solar eclipse that will sweep across the United States is just over a month away. While millions of Americans finalize their plans to view the Aug. 21 spectacle, it is worth remembering that the weather will determine whether you can see it.

Cloudy skies could ruin the eclipse experience and, unfortunately, weather forecasters will not have a good idea as to exactly what areas will be “in the clear” until a few days before.

But researchers at the University of Idaho have attempted to come to the rescue by developing a map which shows — based on historical data — what areas will most probably have clear skies.

“[T]his map is unique because we have added information on the probability of clear skies — meaning how well you will actually be able to see the eclipse from where you are located in the U.S.,” said Luigi Boschetti, an associate professor of remote sensing at the University of Idaho.


A map shows the likelihood of clear skies on Aug. 21, along the path of totality during the solar eclipse. (University of Idaho)

Boschetti and Andrea Melchiorre, a PhD student, used 16 years of cloud data from NASA’s Terra satellite, to develop the map which shows clear skies probabilities for the entire United States.

Along the path of totality, where the moon will completely block out the sun’s face, the map shows locations in the interior West having the highest chance of clear skies (shaded in blue) and lower chances (shaded in yellow) as you head east.

It is generally consistent with a similar map showing historical cloud cover on Aug. 21 developed by the National Oceanic and Atmospheric Administration (NOAA).


Via NOAA: “The darker the dot, the greater the chance for cloudiness at the hour of peak viewing during the total solar eclipse on August 21, 2017. Dots represent automated weather stations that reported the cloudiness data and show the 10-year cloudiness average for August 21, 2001-2010.”

To develop its map, NOAA incorporated just 10 years of data and relied on cloud cover information from ground observations, rather than satellite data.

The NOAA map is also different in that it indicates the average percentage of cloud cover across the nation over the years whereas the University of Idaho map conveys how frequently skies have been totally clear.

For example, the University of Idaho map shows Rexburg, Idaho has a 60-70 percent chance of clear skies, while Nashville, Tenn. has a 30-40 percent chance of clear skies.

But skies don’t have to be totally clear to see the eclipse, as long as cloud cover is only partial so don’t be too discouraged by the lower chances in the Southeast.

To download high-resolution versions of the University of Idaho map, visit this website: Researchers Show Locations of Clearest Skies for Solar Eclipse

Link: More eclipse coverage from The Washington Post