Coolest US Cities in Summer

Cool summer temperatures can be found in major cities of the United States on the west coast and in the northeast.

Among the country's 51 largest cities, San Francisco tops the list for usually having the coldest weather each day in June, July and August. San Francisco's mean summer temperature is barely above 60 degrees Fahrenheit, whereas most major US cities average at least 70 °F (21 °C) during summer.

These rankings of coldest cities use long-term temperature averages, based on weather data collected from 1981 to 2010 for the NOAA's National Climatic Data Center.

The major cities included in the weather rankings represent the 51 metropolitan areas in the United States with the most people, all those with over one million residents in 2010, according to the US Census Bureau.

US cities with the lowest normal daily mean temperatures for June, July and August

City	Daily Summer Mean
	°F	°C
San Francisco, California	61	16
Seattle, Washington	65	18
Portland, Oregon	67	19
Rochester, New York	69	20
Buffalo, New York	69	21
San Jose, California	69	21
San Diego, California	69	21
Milwaukee, Wisconsin	70	21
Denver, Colorado	71	22
Pittsburgh, Pennsylvania	71	22
Boston, Massachusetts	71	22
Minneapolis, Minnesota	71	22
Providence, Rhode Island	71	22
Hartford, Connecticut	71	22

Coolest Summer Days

Every major US city, except Buffalo, has set a record high temperature of 100 °F (37.8 °C) or more. Still, 14 of the biggest American cities don't reach temperatures above 80 °F (27 °C) during an average summer day. Making 90 °F (27 °C) is an especially rare event in Seattle, San Diego, San Francisco and Buffalo, where it normally gets that hot on less than three days a year.

US cities with the lowest normal daily maximum temperatures for June, July and August

City	Average Daily Maximum
	°F	°C
San Francisco, California	67	19
San Diego, California	74	23
Seattle, Washington	74	24
Buffalo, New York	78	26
Milwaukee, Wisconsin	78	26
Portland, Oregon	78	26
Boston, Massachusetts	79	26
Rochester, New York	79	26
Providence, Rhode Island	81	27
Cleveland, Ohio	81	27
Minneapolis, Minnesota	81	27
San Jose, California	81	27
Pittsburgh, Pennsylvania	81	27
Detroit, Michigan	81	27

Lowest Summer Temperatures

Nighttime temperatures don't normally drop below 40 degrees in summer at any of America's largest cities. And only rarely during June, July or August does a large US city experience freezing weather.

Temperatures in eleven of the 51 major American urban centers regularly go down below 62 °F (17 °C) during the summer. The cities most likely to have cool nights are Portland, Denver and Rochester, where temperatures of 50 °F (10 °C) or colder happen an average of 10 or 11 times a summer.

US cities having the lowest normal daily minimum temperatures for June, July and August

City	Average Daily Minimum
	°F	°C
San Francisco, California	54	12
Portland, Oregon	55	13
Seattle, Washington	56	13
Denver, Colorado	57	14
Sacramento, California	57	14
San Jose, California	58	14
Rochester, New York	59	15
Buffalo, New York	60	16
Hartford, Connecticut	60	16
Pittsburgh, Pennsylvania	61	16
Milwaukee, Wisconsin	61	16