Extreme Heat Warnings are active again today, issued by NWS offices across the middle of the country and the Southwest. Reported heat index values: up to 117 in parts of Missouri and south-central, southwest and west-central Illinois (NWS St Louis); up to 115 across southwest Missouri and southeast Kansas (NWS Springfield); up to 113 in northeast Kansas and northern Missouri (NWS Kansas City). Warnings are also in force from NWS Phoenix and NWS San Diego, with alerts covering Iowa and Nebraska. Most run to the evening of July 27 or the morning of July 28. Check weather.gov for your exact county - warnings are drawn by county, not by state.
Earlier - July 21, 2026: Extreme heat warnings are in effect across the Heartland, with heat index values of 110°F or higher and readings near 116°F around Owensboro on the Kentucky-Indiana line. Arkansas’s warning runs through at least Tuesday; Oklahoma expects alerts most days this week. Alerts shift county by county — verify yours at weather.gov.
Weeks after the late-June heat dome put more than 200 million Americans under dangerous heat, the center of the country is cooking again. Here is what is confirmed, what the numbers mean, and how long forecasters expect it to run.
Where the Extreme Heat Warnings Are (Confirmed)
- Arkansas — much of the state under an extreme heat warning through at least Tuesday, with triple-digit heat hitting Northwest Arkansas and the River Valley, per the Arkansas Democrat-Gazette and KNWA.
- Kentucky–Indiana (Owensboro area) — heat index near 116°F, among the most extreme readings in the country right now.
- Oklahoma — forecasters at KOKH say heat alerts “should be expected most days this week.”
Warnings are issued county by county and change daily — neighboring states across the mid-South and southern Plains are seeing advisories as well, so check weather.gov for your exact county rather than assuming.
How Hot Is “Heat Index 116” Really?
Afternoon air temperatures are forecast in the mid-to-upper 90s, but the heat index — what it feels like once humidity is added — is running 110° to near 116°. At those values, sweat stops evaporating efficiently, which is the body’s main cooling system. That is why the National Weather Service treats it as dangerous for everyone, not just sensitive groups.
Extreme Heat Warning vs Heat Advisory
- Heat Advisory — hot conditions that can become dangerous if you do not take precautions.
- Extreme Heat Warning — the higher tier: heat dangerous to anyone outdoors. Limit sun exposure, hydrate aggressively, never leave people or pets in cars, and check on elderly neighbors.
How Long Will It Last?
The confirmed windows: Arkansas through Tuesday, Oklahoma most of this week. The pattern echoes this summer’s defining weather story — the heat dome, a stalled ridge of high pressure that traps hot, humid air for days or weeks. The late-June version parked heat index values near 110° over the eastern two-thirds of the country into the July 4 weekend.
Staying Safe in 110°+ Heat
- Shift outdoor work to early morning or after sunset; the 2-6pm window is the most dangerous.
- Drink water before you feel thirsty; thirst lags dehydration.
- Know the difference: heat exhaustion = heavy sweating, weakness, nausea; heat stroke = confusion, hot dry skin, passing out — that one is a 911 call.
- Check on elderly neighbors and anyone without air conditioning; most heat deaths happen indoors.
Frequently Asked Questions (FAQ)
Which states are under extreme heat warnings?
Confirmed as of July 21: much of Arkansas, the Owensboro KY-IN region and Oklahoma, with the mid-South and southern Plains under various heat alerts. Check weather.gov for your county — alerts change daily.
How hot will it feel?
Heat index 110°+ , peaking near 116° around Owensboro, with triple-digit actual temperatures in parts of Arkansas.
What is the difference between a warning and an advisory?
An advisory means dangerous if unprepared; a warning means dangerous for anyone outdoors — the higher tier.
How long will this heat last?
Arkansas through at least Tuesday; Oklahoma expects alerts most days this week.
What is a heat dome?
A stalled high-pressure ridge that traps hot, humid air for days or weeks — the late-June one covered 200+ million Americans.
Warning areas and heat index values per the Arkansas Democrat-Gazette, KNWA, WOMI Owensboro and KOKH, July 20-21, 2026; heat dome context per NPR and Time. Alerts change frequently — always verify current warnings for your county at weather.gov.
