CLARKSVILLE, TN (CLARKSVILLE NOW) – With heat index values expected well over 100 Monday and Tuesday, Montgomery County is under a Heat Advisory from the National Weather Service.

The Advisory is in effect through 8 p.m. Tuesday. Today’s high should be 93, with a 106 index; Tuesday should be 96 with a 113 index.

National Weather Service Heat Advisory for Tuesday, July 21, 2026 (NWS, contributed)
National Weather Service Heat Advisory for Tuesday, July 21, 2026 (NWS, contributed)

“Hot temperatures and high humidity may cause heat illnesses,” the NWS said. “Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check on relatives and neighbors.”

Clarksville forecast

Here’s the day-by-day outlook:

  • Monday: A 30 percent chance of showers and thunderstorms, mainly between 1pm and 2pm. Patchy fog before 9am. Otherwise, mostly sunny, with a high near 93. Heat index values as high as 106. Calm wind becoming west around 5 mph.
  • Monday night: Partly cloudy, with a low around 74. Calm wind.
  • Tuesday: A 30 percent chance of showers and thunderstorms, mainly between 4pm and 5pm. Mostly sunny, with a high near 96. Heat index values as high as 113. Southwest wind 5 to 10 mph.
  • Tuesday night: Showers and thunderstorms before 4am, then a chance of showers. Low around 73. West southwest wind around 5 mph becoming calm in the evening. Chance of precipitation is 90%.
  • Wednesday: Sunny, with a high near 86. North wind 5 to 10 mph.
  • Wednesday night: Partly cloudy, with a low around 64. North northeast wind 5 to 10 mph.

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