The entire state of Tennessee has been under an oppressive heat dome for days, but the sweltering weather could break soon.
The strongest heat dome in the world reached Tennessee on Sept. 16, according to digital meteorologist Ryan Hall.
"High humidity, limited cloud cover and light winds" make the air trapped within the heat dome feel even hotter, according to NASA. A heat dome lets sunlight reach the ground unabated and further raises temperatures.
Shop hot weather essentials as summer heat lingers on
While meteorological fall starts at the beginning of September, astronomical fall, which is more commonly observed, begins toward the end of the month and brings cooler temperatures to Tennessee.
Here's when cities across Tennessee could see true
fall weather arrive.
When will it cool down in Tennessee?
Technically, Tennessee has already begun its descent into cooler weather, as the state hits its peak maximum temperatures in July.
In Tennessee, the maximum temperature will hit 70 degrees sometime in October, depending on where you are in the state.
Knoxville is typically the first major Tennessee city to see highs fall to 70 degrees, usually by mid-October. Memphis and Nashville both see a daily maximum temperature of 70 degrees around the end of October, up to two weeks later than Knoxville.
When will it cool down in Knoxville?
The timing of crisp fall air arriving in East Tennessee is hard to say for sure, but what is certain is that higher-than-normal temperatures will continue throughout the month, according to Morristown National Weather Service Meteorologist Nathan Wellington.
It's difficult to predict the weather beyond the seven-day forecast in too much detail, according to Wellington. But he predicts East Tennessee will see a bit of relief in October.
"It's a little hard to say at this point (when temperatures will cool down)," Wellington said. "Late September into October it should cool down."
High temperatures averaging in the mid-80s will continue through September. In October, average temperatures will peak around 74, and temperatures will continue to decrease as daylight shortens.
Knoxville will begin to see a break in the heaton Sept. 23 when the high for the day is only 83 degrees. The next day is forecast to bring a high of 81 degrees.
When will it cool down in Memphis?
Daytime temperatures in Memphis will remain in the high 90s for the third week of September. Sept. 22 will bring a break in the heat, with a high of only 92 degrees. Lows will linger between the upper and lower 70s.
"Right now there isn't much sign of fall weather for the Memphis area," the National Weather Service for Memphis wrote in an email. "The latest temperature outlook through the end of the month keeps our area in above-average temperatures. We may cool down a few degrees next week, but our highs remain in the low 90s."
From Sept. 1-30, the normal maximum temperature in Memphis drops by eight degrees, from 90 degrees to 82 degrees. The normal maximum temperature typically reaches the 80s around Sept. 4, but according to the National Weather Service, September has been the hottest month thus far in 2026.
Memphis is also expected to have a break in the heat beginning Sept. 23 when the high reaches only 87 degrees, followed by 86 degrees on Sept. 24.
When will it cool down in Nashville?
According to the National Weather Service office in Nashville, temperatures are expected to remain above normal through the rest of September, with little sign of a sustained fall cooldown.
"Hopefully the heat will ease next week, but we do not see any ‘pumpkin spice’ weather on the way yet,” said National Weather Service meteorologist Sam Herron in an email to The Tennessean.
Long-range forecasts indicate temperatures could trend closer to seasonal norms in October. According to Herron, Middle Tennessee typically experiences a "false fall" before cooler weather settles in for good, as both spring and fall are marked by frequent swings between warm and cool conditions.
Nashville’s average temperature for September is 73 degrees, with normal precipitation totaling 3.80 inches. In October, the average temperature drops to 61.7 degrees, with 3.36 inches of rainfall. By November, the average temperature falls to 50.3 degrees, while normal precipitation increases slightly to 3.86 inches.
The sweltering heat in Nashville is expected to lift on Sept. 23, with a high of only 84 degrees, followed by a high of 83 degrees on Sept. 24.
When is the first day of fall?
The break in the heat, coincidentally, follows only a day after astronomical fall begins.
The astronomical season is based on the Earth's position relative to the sun, so fall begins on the autumnal equinox, which takes place on Sept. 22, 2026.
For meteorologists, fall begins earlier than the autumnal equinox. The meteorological fall season starts Sept. 1 and runs through Nov. 30, aligning with the calendar months used to track seasonal weather patterns.
Jordan Green covers trending news for The Commercial Appeal and Tennessee. She can be reached at jordan.green@commercialappeal.com.
This article originally appeared on Nashville Tennessean: When will it cool down in Tennessee? What forecasters are saying
Our editors independently choose our recommendations. Some content is produced with paid support from a third party, however our editorial decisions remain independent. If you buy through our links, the USA TODAY Network may earn a commission. Prices and availability may change.
