Hottest US Cities in Summer

Among the largest cities in the United States, Phoenix and Las Vegas stand out as consistently having remarkably hot weather during the months of June, July and August. This is most apparent in the number of days they endure with highs in the 100s Fahrenheit (over 37 degrees Celsius). The data here look at several different temperature measures of the US cities with the hottest summertime weather.

These ratings of hottest cities use long-term temperature averages for the three summer months, June, July and August, based on weather data collected from 1991 to 2020 for the US National Centers for Environmental Information. The major cities included in these weather rankings represent the 56 metropolitan areas in the United States with the most people, all those with over one million residents in 2020, according to the US Census Bureau.

Highest Summer Temperature Overall

Phoenix and Las Vegas are the two major cities with an average temperature throughout summer that's above 90 degrees Fahrenheit (32 °Celsius). Another ten US cities have average summer temperatures in the 80s.

US cities with the highest normal daily mean temperatures in June, July and August

City	Mean °F	Mean °C
Phoenix, Arizona	94	34
Las Vegas, Nevada	91	33
Dallas, Texas	86	30
Austin, Texas	85	30
San Antonio, Texas	84	29
Houston, Texas	84	29
Miami, Florida	84	29
Tampa, Florida	84	29
New Orleans, Louisiana	83	29
Jacksonville, Florida	83	28
Orlando, Florida	83	28
Memphis, Tennessee	82	28

City links take you to more detailed information on temperatures for that location. You can also view a summary of temperature averages for all major US cities and city temperatures in recent years and a complete list of America's 56 largest urban centers.

Hottest Summer Days

Only at Phoenix, Tucson and Las Vegas do highs in the 100s F occur on most summer days. For the other 14 cities that exerience high temperatures on at least two-thirds of summer days, the thermometer more commonly heats up into the 90s. But not all cities that frequently have 90-degree weather can expect temperatures topping 100 each year. In Florida and Louisiana, several hot cities don't experience 100-degree weather.

These 17 major cities most often have temperatures reaching 90 °F during summer.

Number of days in summer when the temperature climbs to at least 90 or 100 °F

City	90 °F 32 °C	100 °F 38 °C
Phoenix, Arizona	91	80
Las Vegas, Nevada	88	67
Tucson, Arizona	88	55
Austin, Texas	82	26
San Antonio, Texas	81	16
Fresno, California	79	33
Dallas, Texas	79	20
Houston, Texas	73	3
Orlando, Florida	71	0
Jacksonville, Florida	67	2
New Orleans, Louisiana	64	0
Miami, Florida	64	0
Sacramento, California	62	19
Riverside, California	61	14
Tampa, Florida	61	0
Oklahoma City, Oklahoma	60	12
Tulsa, Oklahoma	60	10

Warmest Cities at Night

A few American cities don't often cool down much at night during summer. Miami can expect every night during summer to remain above 70 degrees. Overall though, Phoenix has the hottest nights, which average above 80 °F for the season.

For the twelve cities listed below, nighttime temperatures stay above 70 degrees on all but a handful of nights in summer. All other major US cities usually see 23 or more nights a summer when it cools off to below 70.

Number of nights during summer when the temperature drops to 70 °F or below

City	70 °F 21 °C
Miami, Florida	0
Tampa, Florida	2
Phoenix, Arizona	2
Honolulu, Hawaii	3
Orlando, Florida	3
Houston, Texas	3
Jacksonville, Florida	4
New Orleans, Louisiana	6
Las Vegas, Nevada	8
San Antonio, Texas	10
Dallas, Texas	10