Will Illinois see a hot, muggy summer this year? What forecasters, almanac predict
After an unusually stormy period in the metro-east and St. Louis, residents can look forward to the beginning of meteorological summer Sunday, June 1.
The summer solstice officially kicks off the new season Friday, June 20, but forecasters expect warm temperatures to arrive sooner.
In the short-term, the metro-east and St. Louis region has a roughly 60 to 70% chance of warmer-than-normal temperatures, according to the federal Climate Prediction Center’s eight to 14 day outlook.
The latest forecast as of May 7 also calls for near-normal precipitation in the short-term for the region, after a period with unusually high rainfall amounts.
“It was kind of a perfect scenario to send a lot of moisture out of the south and interact over the central U.S. and produce a lot of thunderstorms and unfortunately severe weather and tornadic activity that we saw ramp up in mid-March,” Jared Maples, meteorologist with the National Weather Service St. Louis office, said in a May 7 interview with the News-Democrat.
March 14 saw “one of the most active outbreaks on record” for the St. Louis County warning area, with 12 tornadoes reported across southeastern Missouri and southwestern Illinois, according to the NWS.
“I know we were pretty well ahead of the game as far as the frequency or the raw number of tornadoes,” Maples said.
Active spring weather continued into the following month. The St. Louis area broke April’s total monthly precipitation record this year, with 10.85 inches compared to the previous record of 10.84 inches. The previous rainfall record was set in 1893, and normal precipitation for April is 4.73 inches.
Here’s what to know about this summer’s weather, including forecast information from the NWS and a prediction from the popular Farmers’ Almanac.
Summer weather forecast
The Climate Prediction Center released its latest three-month seasonal outlook April 17 for May, June and July.
The outlook calls for a 33 to 40% chance of above-normal temperatures in the metro-east and St. Louis region.
“That being said, that doesn’t really address the degree of how far above normal,” Maples said.
The seasonal precipitation outlook reports the greater St. Louis and southwestern Illinois region has roughly equal chances of above- or below-normal precipitation.
Here are summertime precipitation and temperature normals for Belleville, using NWS data from 1991 to 2020:
June:
Total normal precipitation: 4.62 inches
Average overall temperature: 75.9 degrees Fahrenheit
Average low temperature: 64.5 degrees
Average high temperature: 87.3 degrees
July:
Total normal precipitation: 4.03 inches
Average overall temperature: 79 degrees
Average low temperature: 67.8 degrees
Average high temperature: 90.2 degrees
August:
Total normal precipitation: 3.92 inches
Average overall temperature: 77.2 degrees
Average low temperature: 65.3 degrees
Average high temperature: 89.1 degrees
What does the Farmers’ Almanac predict?
The Farmers’ Almanac predicts hot, stormy weather for most of the U.S. this summer.
The prediction for Illinois and surrounding states calls for a “sultry, thunder-filled” season, while the regional zone, including Missouri, can expect “scorching” temperatures with “average rainfall,” according to the almanac.
The almanac also provides a specific prediction for Memorial Day weekend, May 24 to May 27. The holiday prediction for Zone 2, which includes Illinois, reads: “Unsettled weather spreads into Ohio Valley, unfortunately dampening Memorial Day weekend. Indy-500 could be wet.”
The forecast for Zone 4, which includes Missouri, indicates it could be “wet on Memorial Day.”
The Farmers’ Almanac makes predictions based on a mysterious formula that considers factors such as planetary positioning, sunspot activity and tidal action of the moon.
“The only person who knows the exact formula is the Farmers’ Almanac weather prognosticator who goes by the pseudonym of Caleb Weatherbee,” the organization’s website says. “To protect this proprietary formula, the editors of the Farmers’ Almanac prefer to keep both Caleb’s true identity and the formula a closely guarded brand secret.”
The almanac has provided extended predictions since 1818, according to its website.
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