The Hottest States and Cities in America, Ranked by 75 Years of NOAA Data

Texas takes the top spot partly because it's enormous — 254 counties worth of weather stations, most of them baking in the southern half. The Rio Grande Valley and Trans-Pecos region are borderline uninhabitable in July without AC. Laredo routinely clears 100°F for weeks straight, and Dallas pushes 97°F on an average summer day. But the Panhandle pulls the statewide average down — Amarillo's summer highs average only 91°F.

Oklahoma surprises people by ranking above Arizona. The difference is consistency — Oklahoma's heat is relentless. The entire state sits on the southern Great Plains where hot air flows north from Texas with nothing to block it. OKC averaged 18 days above 100°F per year since 1990. In 2011, the state broke or tied the US record with 63 consecutive days above 100°F in Oklahoma City.

Arizona's statewide average is deceptively moderate because Flagstaff (elevation 7,000 ft) averages just 80°F in summer. But at lower elevations, it's a different planet. Phoenix AP averages 105.4°F in summer. Arizona stations average 48.6 days above 100°F per year — more than double the next-closest state. The dry heat is real, but 120°F is 120°F regardless of humidity.

Louisiana's thermometer readings look similar to Oklahoma's, but the experience is far worse. Gulf moisture pushes humidity above 70% most summer afternoons, making a 92°F day feel like 105°F. New Orleans' heat index regularly exceeds 115°F in July and August. The state rarely breaks 100°F on the thermometer — it doesn't need to.

Florida rarely hits 100°F — its all-time record of 109°F is the lowest all-time high of any state south of Virginia. But Florida doesn't need extreme thermometer readings to be miserable. Summer humidity averages 73% in Miami, and overnight lows stay above 78°F. The heat never breaks. Florida is the hottest state by average annual temperature (72.6°F), but ranks 5th by summer highs alone because its winters inflate the annual average.

Mississippi shares Louisiana's Gulf moisture problem. The state's low elevation (average 300 ft) means no topographic relief from the heat. Jackson averages 91°F summer highs with 65%+ humidity, giving heat index values around 107°F on a typical July afternoon.

Arkansas holds one of only four 120°F records in the US, set during the catastrophic 1936 Dust Bowl summer. The Ozark Plateau provides some relief in the northwest, but the Mississippi Delta region in the east is flat, humid, and relentlessly hot. Little Rock averages 9 days above 100°F annually.

Alabama's heat is the Deep South standard: high 80s to low 90s on the thermometer, but brutal humidity makes it feel much worse. The Tennessee Valley in the north gets marginally cooler summers, while the Gulf Coast stays above 88°F from June through September. Mobile averages 89°F summer highs with oppressive humidity off the Gulf.

Kansas sits at the intersection of southern heat and Great Plains geography. Hot air slides north from Texas and Oklahoma across hundreds of miles of flat cropland with nothing to slow it down. The western half is drier and slightly hotter than the east. Kansas held the US record at 121°F for nearly 50 years (1936–1983). Wichita averages 12 days above 100°F per year.

Georgia's Piedmont region around Atlanta averages 89°F summer highs, with humidity pushing heat index values into the low 100s most afternoons. The coastal plain south of Macon is hotter and wetter. Atlanta's urban heat island adds 5-8°F to overnight lows compared to surrounding suburbs, making it harder for the city to cool down at night.

Phoenix isn't just the hottest major city in America — it's in a different league. The average summer day hits 105.4°F, and the city has averaged 107 days above 100°F per year since 1990. In 2023, Phoenix recorded 31 consecutive days above 110°F. The urban heat island is so intense that overnight lows frequently stay above 90°F — rare in most desert cities.

Las Vegas has warmed faster than any major US city since 1990 — up 4.8°F. The metro tripled in population since 1990, replacing desert with concrete and asphalt that radiates heat long after sunset. The Strip's casino floors stay 72°F, but the parking lots hit 140°F+. In 2024, Vegas recorded 13 consecutive days above 115°F.

Tucson gets one advantage Phoenix doesn't: the monsoon. Starting in late June, moisture streams north from the Gulf of California, dropping afternoon thunderstorms that briefly cool the city. But pre-monsoon June is brutal — averaging 103°F with near-zero humidity. The monsoon start date has shifted about 10 days later since the 1990s, extending the dry furnace phase.

San Antonio sits at the boundary where dry West Texas heat meets Gulf moisture. The result is the worst of both worlds — thermometer readings in the upper 90s with enough humidity to push heat index values past 108°F regularly. The city's sprawling suburbs over limestone Hill Country terrain trap and re-radiate heat.

Dallas sits on the blackland prairie where hot air from the southwest meets Gulf humidity. Average summer highs push 95°F, but the city regularly smashes through 100°F. The DFW metro's 7,300 square miles of development creates one of the nation's most intense urban heat islands. In 2011, Dallas hit 100°F on 71 consecutive days.

Austin's population nearly tripled since 1990 (465K to 1.1M), replacing Hill Country ranchland with development. The limestone bedrock stores and radiates heat efficiently. In 2023, Austin recorded 45 consecutive days above 100°F. Drought years, which are increasingly common under El Nino patterns, supercharge temps by removing evaporative cooling from the landscape.

Sacramento's Central Valley location acts as a heat trap — the Sierra Nevada and Coast Range block marine air from both directions. June through September is virtually rain-free. The city hit 116°F in September 2022, shattering its all-time record. Agricultural irrigation in the surrounding Valley is declining, removing a source of evaporative cooling.

OKC sits at the southern end of the Great Plains heat corridor. Hot air flows north from Texas unimpeded across flat terrain. The city's mix of heat and humidity pushes heat index values past 100°F almost daily in July. In 2011, OKC recorded 63 consecutive days above 100°F — a modern US record for any major city.

Houston's thermometer readings are moderate by Texas standards, but its heat index tells a different story entirely. With summer humidity averaging 65%, a 92°F afternoon feels like 112°F. Houston may have fewer days above 100°F than Dallas or Austin, but it has more days where the heat index exceeds 110°F than any other major US city. The Gulf moisture never relents.

Miami almost never hits 100°F on the thermometer — its all-time record is just 100°F. But with 73% average summer humidity, 90°F feels like 108°F. And unlike desert cities that cool to 75°F at night, Miami's overnight lows stay above 78°F in July and August. The heat never breaks. Coral Gables and inland suburbs are 3-5°F hotter than the beach.