Thunderstorm Activity is Peaking in Parts of the United States

Brian Donegan
Published: July 13, 2017

Thunderstorm activity peaks at different times of the year across the United States, and right now, we've reached the peak of the season in some parts of the country.

July 7-13 is when thunderstorm activity peaks for large swaths of the Northeast, upper Midwest, northern Plains and northern Rockies.

(MORE: It's Prime Time for Damaging Winds in the United States)

According to climatologist Dr. Brian Brettschneider with the University of Alaska-Fairbanks and the Western Regional Climate Center (WRCC), the exact dates for some select cities in these regions are as follows:

  • Rapid City, South Dakota: July 7
  • New York City (La Guardia Airport): July 8
  • Boston: July 8
  • Milwaukee: July 8
  • Detroit: July 8
  • Great Falls, Montana: July 9
  • Glasgow, Montana: July 9
  • Denver: July 10
  • Burlington, Vermont: July 10
  • Albany, New York: July 11
  • Bismarck, North Dakota: July 12
  • Cheyenne, Wyoming: July 13
  • Green Bay, Wisconsin: July 13

This map shows the median date of peak occurrence for thunderstorms across the United States.
(Dr. Brian Brettschneider/WRCC)

Around this time of year, parts of these regions enjoy their warmest time of the year, which is likely why thunderstorm activity also peaks now.

(MORE: July is the Warmest Time of the Year for Much of the U.S.)

Other areas that see peak thunderstorm activity July 7-13 include Southeast coastal areas and the Gulf Coast. New Orleans, for example, peaks July 12, while Savannah, Georgia, peaks July 11.

Portions of the southern Plains peak before June 23 since they receive the bulk of their thunderstorms in April and May during the heart of severe weather season. In spring and early summer, warm, humid air masses interact with Gulf of Mexico moisture drawn up from the south, hence the earlier peak in the southern Plains.

(MORE: Why Pop-Up Summer Thunderstorms Are Among the Hardest Weather to Predict)

The Desert Southwest sees the latest peak in thunderstorm activity, not occurring until late July or early August. The reason for this is the Southwest summer monsoon, which gradually sets in through July. The monsoon brings increased moisture to the region, providing fuel for thunderstorm development in a typically dry area for most of the year.

(MORE: Southwest Monsoon 2017 Forecast)

Brian Donegan is a digital meteorologist at weather.com. Follow him on Facebook and Twitter.

MORE: Severe Storms in the Midwest, Northeast, July 7, 2017


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