What is the hottest SF gets?

The hottest temperature ever recorded in San Francisco (SF) was 106 degrees Fahrenheit (41.1°C) on September 1, 2017, a record that broke the previous high of 103°F. This extreme heat event, unusual for the city, hit downtown areas and was part of a larger California heatwave, with SFO airport also setting a September record at 104°F.

What's the hottest it gets in SF?

The hottest it's ever been in SF was 106 degrees, which occurred on September 1, 2017.

How hot can SF get?

Over the course of the year, the temperature typically varies from 45°F to 72°F and is rarely below 39°F or above 83°F.

Has San Francisco ever hit 100?

On Sept. 6, 2020, San Francisco hit 100 degrees — a rare event in the city's recorded history.

What is San Francisco's hottest month?

While August can see high temperatures, September is generally considered San Francisco's hottest month, often with the warmest and sunniest days as the marine layer (fog) retreats, leading to warmer inland air reaching the coast, with October also being very warm.
 

How Hot Can It Get?

Is San Francisco warm in May?

Usually, the San Francisco weather in May starts off with cool, partially overcast mornings with temperatures in the mid-50s. This typically burns off mid-morning. Then you can expect mostly sunny afternoons and temperatures warm to the mid-60s. At night, a light layer of clouds usually covers SF again to cool it off.

What is hotter, July or August?

July is the hottest month of the year for most of the country. Many regions in the United States—from the Rockies to the East Coast—follow this pattern. However, this isn't true for all regions.

Is 40 degrees too hot for humans?

The human body is built to operate at a core temperature of about 37C degrees. We become more light-headed and prone to fainting as the core rises closer to 40C. High core temperatures damage our body's tissues, such as heart muscle and the brain. Eventually this becomes deadly.

Is 2025 the coldest summer in San Francisco?

2025 has been SFO's coldest summer since 1965, OAK's since 1975, and San Jose's coldest since 1999.

When was it 134 in California?

The world record, also recorded at Death Valley, was 134 degrees in July 1913. More than 210 degrees Fahrenheit separates the highest and the lowest temperatures on record in the United States, the third-largest country in the world.

Why is there no AC in San Francisco?

WEATHER. San Francisco, San Jose, and Seattle have the lowest rates of air-conditioned homes in the nation, research shows. Weather is, of course, an obvious factor, as the Pacific Northwest has historically had milder summers, leading to less of a need for home cooling.

Can SF get tornados?

The state averages nine tornadoes per year, with most of those in coastal areas in winter and the Central Valley in spring. In December 2024, a tornado in Scotts Valley (Santa Cruz County) flipped vehicles and injured people. The same day, a tornado warning was issued in San Francisco.

Why does SF feel so cold?

San Francisco feels so cold due to its unique geography, particularly its proximity to the chilly Pacific Ocean, which brings cool, dense marine air and frequent fog (the "marine layer"), especially in summer, creating a damp chill and blocking the sun, even when inland areas are hot. Cold, deep ocean currents and onshore winds enhance this effect, making temperatures stay mild or even chilly year-round, leading to the classic SF experience of needing layers even in July. 

Is LA warmer than SF?

A: Los Angeles tends to be slightly warmer than San Francisco. On average, LA temperatures range from an annual high of 72 degrees to an annual low of 56 degrees, compared to San Francisco's average high of 64 degrees and average low of 51 degrees.

Has it ever snowed in SF?

San Francisco's all-time record snowfall occurred on February 5, 1887, when 3.7 inches were measured at the downtown weather bureau location in the financial district. At higher elevations in the western portion of the city, the snow was 7 inches deep.

Was June 2025 hotter than June 2024?

June 2025 had the third-warmest June global surface temperature in NOAA's 176-year record, with a temperature 1.76°F (0.98°C) higher than the 20th-century baseline. This June was cooler than June 2023 (second warmest) and June 2024 (warmest).

Will 2025 be hotter or colder than 2024?

How hot is it? 2025 is shaping up to be among the warmest years on record, behind 2024 but rivaling 2023.

Was the coldest winter I ever had was a summer in San Francisco?

Mark Twain said: “The coldest winter I ever spent was a summer in San Francisco.” Myth. While it's true that Twain didn't like our city very much, there is no proof that he ever said this about San Francisco. He did write something similar about Paris, although even then he was quoting someone else.

How hot will the temperature be in 2050?

Since 1880, average global temperatures have increased by about 1 degrees Celsius (1.7° degrees Fahrenheit). Global temperature is projected to warm by about 1.5 degrees Celsius (2.7° degrees Fahrenheit) by 2050 and 2-4 degrees Celsius (3.6-7.2 degrees Fahrenheit) by 2100.

How hot is too hot for life?

Temperatures above 95°F (35°C) wet-bulb (heat + humidity) become extremely dangerous as the body can't cool itself, risking heat stroke, while sustained indoor temps over 82°F (28°C) are considered unsafe, especially for vulnerable groups, highlighting that "too hot" depends on humidity, duration, and individual health, with wet-bulb temps above 95°F (35°C) being a key physiological limit. 

Can a human survive 200 degrees Fahrenheit?

Yes, a human can survive 200°F (93°C) for short periods, especially in dry heat like a sauna, thanks to sweating, but prolonged exposure is extremely dangerous and potentially fatal as the body overheats (hyperthermia) and internal organs suffer damage, leading to heat stroke, especially with humidity or inactivity. Survival depends heavily on hydration, ventilation, acclimatization, and the body's ability to cool itself effectively. 

Is 72 degrees too hot to sleep?

72°F (22°C) is generally considered the upper end of the ideal sleep temperature range (60-72°F), so it's not too hot for many, but it might be starting to get warm for optimal deep sleep, potentially causing lighter, less restful sleep, though it's much better than very hot rooms; listen to your body and adjust with lighter bedding if you feel too warm, as individual comfort varies. 

Is California the hottest state?

No, California isn't consistently the hottest state overall; Florida generally holds that title due to its year-round warm and humid climate, but California has recorded the single highest temperature ever in the U.S. (Death Valley) and experiences extreme heat in its desert regions, making it exceptionally hot at certain times and places. While Florida leads in average annual temperature, California's vast deserts can reach extreme highs, often over 100°F in summer. 

Is September still hot in California?

Autumn (September through November) brings mild weather and, in some parts of the state, spectacular foliage (especially the High Sierra).

Is it really getting hotter every summer?

Change in average summer temperatures, 1970-2024

Summers are getting warmer nearly nationwide, a recently updated analysis finds.