Take Newport, Oregon, for instance, the first land-based weather station location in the path of the full eclipse. The eclipse will occur there at approximately 10:15 a.m. local time (17:15 UTC). The viewable percentage is 44 percent, meaning there’s a 56 percent chance that viewability will be adversely affected by clouds. Keep in mind the percentage is an estimate of average conditions, not a guarantee for this year.
Only an estimated 12 million people live within the relatively narrow area of the total eclipse. However, several major cities and five state capitals fall within the path of totality—the narrow band where the moon completely blocks the sun’s face. Visit the CICS-NC interactive map to search for an optimal viewing location by zip code.
Find a Seat for the Total Eclipse
From its first appearance over the Pacific Northwest in midmorning, the eclipse will last approximately 90 minutes, ending shortly after 2:45 p.m. local time (18:45 UTC) on the South Carolina coast near Charleston. Here’s a partial list of towns and cities on the path of totality from west to east along with estimated local times for peak viewing of the total eclipse, followed by the average historical cloudiness percentage (state capitals in bold; asterisks indicate larger airports):
||10:15 a.m. (PDT)
||10:17 a.m. (PDT)
||10:17 a.m. (PDT)
||11:32 a.m. (MDT)
||11:42 a.m. (MDT)
||11:49 a.m. (MDT)
||1:02 p.m. (CDT)
||1:07 p.m. (CDT)
||1:13 p.m. (CDT)
||Chesterfield near St. Louis
||1:16 p.m. (CDT)
||1:19 p.m. (CDT)
||1:22 p.m. (CDT)
||1:27 p.m. (CDT)
||1:27 p.m. (CDT)
||2:37 p.m. (EDT)
||2:38 p.m. (EDT)
||2:41 p.m. (EDT)
||2:45 p.m. (EDT)
|The percentage represents the likelihood of favorable viewing conditions. A higher percentage means the view is more likely to have fewer clouds.
*Indicates a major airport. State capitals are in bold.
Total or Partial Eclipse
Besides crossing Oregon, Idaho, Wyoming, and South Carolina, the total eclipse takes a relatively swift and narrow route across portions of Nebraska, Kansas, Missouri, Illinois, Kentucky, Tennessee, and North Carolina. The eclipse crosses directly over five state capitals.
Although skies will dim for many, day will turn to night only beneath the path of totality, approximately 70 miles wide on the surface. The farther away from the path of totality, the less the moon will cover the sun from the viewer’s standpoint. Most people will see a partial eclipse due to their location outside the totality.
The interactive map marks shaded areas on either side of the path of totality that represent the zones where the sun will only be partially blocked or obscured. Each station on the interactive map lists this “obscuration” percentage and the peak eclipse time. A filter can be applied on the map to view each obscuration area independently.
Eclipse Essential: Protect Your Eyes
It’s important to take precautions when viewing the eclipse. The partial phases of the eclipse can last between 2 to 3 hours; at its longest, the total eclipse will last 2 minutes and 40 seconds. Direct viewing of the partial phases can cause permanent damage to your eyes because of the intensity of the sunlight. The eclipse should only be viewed with protective eyewear designated for use during an eclipse. Ordinary sunglasses or 3D glasses lack sufficient protection. Also, avoid viewing through unfiltered cameras, telescopes, binoculars, or other optical devices.
However, if weather cooperates during the few minutes that the sun is completely eclipsed in totality, the brief interval is as safe to view as a full moon.
Understanding the Historical Cloudiness Data
Our historical cloudiness data come from 10-year hourly climate normals for 2001–2010 measured at automated weather stations across the country on August 21, as close to the hour of the eclipse as possible. Availability of data determined the number of usable stations. The period 2001–2010 was chosen because a nationwide network of automated observing stations became operational in 1998. This 10-year timeframe allowed hourly normals computation for more than 800 stations.
However, many factors can influence cloudiness. Areas that experience higher humidity, such as coastal Oregon and the Southeast, are more likely to experience cloudy conditions. Other local factors may influence cloudiness and viewability as well, such as mountains and fog. Afternoon convection can also cause pop-up showers and storms. This helps explain the lower viewable percentages over the eastern half of the United States when the eclipse passes through early to midafternoon.
Keep a few other caveats in mind as you look at our maps. Automated weather stations only view clouds from the surface to 12,000 feet. Larger airports also typically have two cloud sensors (ceilometers) whereas smaller airports may only have one. Larger airports often have human observers that can see higher clouds. These differences mean that stations at larger airports tend to detect more clouds, so stations near each other may report different viewability percentages.
Ultimately, the cloudiness calculations are based on past observations, which are no guarantee of future outcomes. For predictions of actual conditions closer to the day of the eclipse, check your location’s forecast at NOAA's Weather.gov as early as seven days prior to the event.
As Brady Phillips of NOAA’s Office of Communications notes, "Even the driest places on Earth experience clouds, fog, and rain.”
Check Back with NCEI for More Eclipse Coverage
Please check back for an “eclipse weather” story from the early 1900s.