Climate and average weather in San Francisco

In San Francisco, the summers are humid, hot, showery, and mostly clear and the winters are mild and mostly clear.

Best: early March to late November

Over the course of the year, the temperature in San Francisco typically varies from 6°C to 30°C, and is rarely below 0°C or above 35°C. January is the hottest month of the year, while July is the coldest.

Based on the travel score, the best time of year to visit San Francisco for warm-weather activities is from early March to late November.

Hottest
Jan
30°
Coldest
Jul
Wettest
Mar
138 mm
Driest
Jul
20 mm
Rain / yr
1021 mm
86 wet days
Daylight
10.0–14.0 h
shortest–longest
Elevation
120 m
31.4°S
Clearest
Aug
37% cloud

San Francisco is city in Argentina.

Founded
1886

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

San Francisco weather by month, at a glance

The whole year in one picture — sky, rain, humidity, temperature and travel score. Click any band to jump to its full chart.

Each stripe is one measure across the whole year, stacked so a single day reads top to bottom. The sky band runs overcast grey on top down to clear blue at the base — more blue means sunnier — followed by the rainfall curve, the humidity band, a temperature strip that tints each stretch of the year by how warm its average high is, and the travel-score line at the foot. Scan straight down any date to read that day across every measure at once; the score climbs highest around early March to late November.

Temperature through the year

Average highAverage lowShaded bands: 10–90% of days

Daily average highs and lows in San Francisco, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.

The hot season lasts 4.4 months, from November 5 to March 18, with daily high temperatures above 27°C. The hottest month of the year in San Francisco is January, with an average high of 30°C and low of 19°C.

The cool season lasts 2.7 months, from May 22 to August 12, with daily high temperatures below 20°C. The coldest month of the year in San Francisco is July, with an average low of 6°C and high of 17°C.

Days typically run about 11°C warmer than nights year-round.

10°20°30°JanFebMarAprMayJunJulAugSepOctNovDec
Avg high (°C)Avg low (°C)
Jan3019
Feb2919
Mar2717
Apr2414
May2011
Jun188
Jul176
Aug208
Sep2211
Oct2514
Nov2816
Dec3018

Average hourly temperature in San Francisco

A compact picture of the whole year, hour by hour: each column is a day, each row an hour, and the color is the modeled average temperature. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.

Read left to right for the day of the year and top to bottom for the hour of the day; the color is the modeled temperature, cool blues through to hot reds on the same scale as the other charts. A vertical slice is a single day's swing — coolest just before dawn, warmest in the mid-afternoon — while a horizontal slice follows one hour across the seasons. The darker overlay marks night and the lighter one the twilight around sunrise and sunset. Colors run warmest on January afternoons, near 30°C, and coldest before dawn in July, near C.

JanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AM

San Francisco weather by month

Every month at a glance. Click a month for its detailed page.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan30° / 19°1199.113.85.3
Feb29° / 19°1159.113.15.8
Mar27° / 17°1389.212.26.8
Apr24° / 14°1008.211.37.4
May20° / 11°475.510.47.1
Jun18° / 304.3106.6
Jul17° / 203.510.26.7
Aug20° / 393.810.97.6
Sep22° / 11°515.411.87.8
Oct25° / 14°1169.612.87.2
Nov28° / 16°1198.913.66.6
Dec30° / 18°1289.6145.5

Chance of rain

How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.

San Francisco gets about 1021 mm of precipitation a year. On a typical day the chance of rain is some rain, but that rises and falls sharply with the seasons.

The wetter season lasts 7.0 months, from around Sep 28 to Apr 27, peaking in March at about 34% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Jul 16.

March is the wettest month by volume, with 138 mm over about 9 wet days; July is the driest, with 20 mm.

0%10%20%30%40%JanFebMarAprMayJunJulAugSepOctNovDecwetterdrierwettermostly drysome rainoften wetMar 1 · 34%Jul 16 · 10%
Rain on a day (%)Rain days
Jan309
Feb329
Mar309
Apr278
May186
Jun154
Jul114
Aug134
Sep195
Oct2910
Nov309
Dec3210

Monthly rainfall

Over a full year, San Francisco collects about 1021 mm of rain across 86 wet days — roughly 85 mm in an average month.

It doesn’t fall evenly. March is the wettest month with 138 mm, while July is the driest at just 20 mm. The three wettest months alone bring about 38% of the year’s total.

0255075100125150175JanFebMarAprMayJunJulAugSepOctNovDec1191151381004730203951116119128
Rainfall (mm)Rain days
Jan1199
Feb1159
Mar1389
Apr1008
May476
Jun304
Jul204
Aug394
Sep515
Oct11610
Nov1199
Dec12810

Clouds and sunshine

ClearMostly clearPartly cloudyMostly cloudyOvercast

How often the daytime sky is clear, partly cloudy or overcast.

In San Francisco, the average share of the sky covered by clouds shows moderate seasonal variation over the course of the year.

The clearer part of the year begins around July 11 and lasts for 2.6 months, ending around September 28. The clearest month is August, when the sky is clear, mostly clear, or partly cloudy 70% of the time on average.

The cloudier part of the year begins around April 1 and lasts for 3.3 months, ending around July 10. The cloudiest month is May, when it is overcast or mostly cloudy 48% of the time.

0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%JanFebMarAprMayJunJulAugSepOctNovDecAug 14 · 72%May 20 · 49%clearmostly clearpartly cloudymostly cloudyovercastcloudierclearercloudier
Clearer (%)Cloudier (%)
Jan6634
Feb6337
Mar6337
Apr6139
May5248
Jun5545
Jul6535
Aug7030
Sep6832
Oct6040
Nov6436
Dec6535

Daylight, sunrise and sunset

DaylightNight

Hours of daylight through the year, with sunrise and sunset times.

The gold band is daylight — sunrise runs along its lower edge, sunset along the upper — so it widens toward summer and pinches toward winter, with night the dark area above and below. The longest day, around January 1, brings about 14 hours of light; the shortest, around June 6, only 10 hours — a swing of roughly 4 hours.

12 AM4 AM8 AM12 PM4 PM8 PM12 AMJanFebMarAprMayJunJulAugSepOctNovDec
Daylight (h)Sunrise (AM)Sunset (PM)
Jan13.86:228:13
Feb13.16:497:57
Mar12.27:117:25
Apr11.37:326:46
May10.47:526:17
Jun10.08:106:08
Jul10.28:106:18
Aug10.97:476:38
Sep11.87:086:57
Oct12.86:307:17
Nov13.66:057:42
Dec14.06:038:06

Sunny days

How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.

San Francisco averages about 15 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 11 and 18 days.

The sunnier stretch runs 2.8 months, from around Jul 7 to Sep 29. The sunniest month is August, with roughly 18 sunny days (bright).

The greyest month is May, down near 12 sunny days — about 32% fewer than the August peak.

0510152025JanFebMarAprMayJunJulAugSepOctNovDecgreyersunniergreyergloomymixedbrightbrilliantAug 1418 daysMay 2211 days
Sunny daysSky
Jan15Mixed
Feb13Mixed
Mar15Mixed
Apr15Mixed
May12Mixed
Jun13Mixed
Jul16Bright
Aug18Bright
Sep16Bright
Oct14Mixed
Nov15Mixed
Dec15Mixed

Humidity comfort

DryComfortableHumidMuggyOppressiveMiserable

Share of days at each humidity comfort level, based on the dew point — the measure that tracks how muggy it actually feels.

Humidity comfort is graded by the dew point — the temperature at which the air would be fully saturated — because it tracks how muggy it actually feels far better than relative humidity does. A low dew point feels dry and crisp; a high one feels sticky and oppressive no matter the reading on a humidity gauge.

In San Francisco, how humid it feels changes dramatically over the year.

The more humid part of the year lasts 4.9 months, from around November 17 to April 13. The muggiest month is January, when the air feels humid, muggy or worse about 80% of the time.

The most comfortable stretch runs from around April 14 to November 16, and July is the most comfortable month — the air is dry or comfortable 98% of the time.

0%10%20%30%40%50%60%70%80%90%100%JanFebMarAprMayJunJulAugSepOctNovDecJul 19 · 98%Jan 24 · 18%oppressivemuggyhumiddrycomfortablehumidcomfortablehumid
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
Jan7142734181
Feb8152534162
Mar1521282691
Apr4126191230
May671711400
Jun82116100
Jul8892000
Aug8884000
Sep82125100
Oct592113610
Nov3927221010
Dec1723282290

Wind

Average wind speed through the year, banded into plain-language speed zones so a number reads as 'breezy' or 'calm' without knowing the scale.

This is the average sustained wind speed at the standard 10 metres above open ground — the steady flow a weather station reports, not the sharper gusts that come and go, which can run half again as fast. It's the number that says whether a place is generally breezy or calm.

Across the year, average wind speed in San Francisco is typically light breeze, near 12 km/h, and varies little with the seasons.

The windier part of the year lasts 5.2 months, from around Jul 11 to Dec 14. The windiest month is September, averaging about 14 km/h (light breeze).

The calmer part of the year runs from around Dec 15 to Jul 10, with February the calmest month at about 11 km/h.

05101520JanFebMarAprMayJunJulAugSepOctNovDeccalmerwindiercalmlight breezeSep 30 · 14 km/hFeb 23 · 11 km/h
Wind speed (km/h)Feels
Jan11calm
Feb11calm
Mar11calm
Apr12calm
May12calm
Jun12calm
Jul12light breeze
Aug13light breeze
Sep14light breeze
Oct14light breeze
Nov13light breeze
Dec12light breeze

Best time to visit San Francisco

TravelBeach/poolTemperatureCloudsPrecipitation

To characterize how pleasant the weather is in San Francisco throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.

Around mid March, San Francisco is still near the start of its best-weather window — great conditions with the peak-season crowds not yet at full swing.

Inferred from the travel-score curve; month-by-month visitor numbers are a planned addition.

The travel score favors clear, rainless days with daytime highs between 18°C and 28°C. Based on this score, the best time of year to visit San Francisco for general outdoor tourist activities is from early March to late November, with a peak score in the third week of September.

0246810JanFebMarAprMayJunJulAugSepOctNovDecbest timetravel scoretemperaturecloudsprecipitationSep 17 · 7.9

The travel score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

Travel score (0–10)Rating
Jan5.3fair
Feb5.8good
Mar6.7good
Apr7.4good
May7.1good
Jun6.6good
Jul6.7good
Aug7.6ideal
Sep7.7ideal
Oct7.2good
Nov6.5good
Dec5.5good

The beach/pool score favors clear, rainless days with daytime highs between 24°C and 34°C. Based on this score, the best time of year to visit San Francisco for hot-weather activities is from late September to late April, with a peak score in the first week of December.

024681012JanFebMarAprMayJunJulAugSepOctNovDecbest timebest timebeach/pool scoretemperaturecloudsprecipitationDec 6 · 7.4

The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

What to pack for San Francisco, by month

EssentialRecommendedOptional

Month by month, what's worth putting in the bag — from the temperature range, rain chance, sun and wind. Tap a month for a quick packing note.

For a warm-season trip around January (highs near 30°C), the essentials are light clothes, rain gear and sun protection. In the cold season around July (highs near 17°C), pack a warm layer.

Light clothing
Warm layer
Winter coat
Rain gear
Sun protection
Windbreaker

In January, San Francisco sees daytime highs around 30°C and nights near 19°C. Pack light clothes and sun protection. Worth having: rain gear. About 9 days see rain.

UV index (midday) in San Francisco by month

LowModerateHighVery highExtreme

Clear-sky midday UV index through the year, shaded by the WHO exposure levels — how much sun protection each month calls for.

Under clear skies, the midday UV index in San Francisco peaks around January 17 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 21 at about 3 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeModerateHighVery highExtremeJan 17UV 14Jun 21UV 3
UV index (midday)Level
Jan14Extreme
Feb13Extreme
Mar11Extreme
Apr7High
May4Moderate
Jun3Moderate
Jul3Moderate
Aug5Moderate
Sep7High
Oct10Very high
Nov11Extreme
Dec13Extreme

Average hourly UV index in San Francisco

LowModerateHighVery highExtreme

Modeled clear-sky UV for every hour of every day — when in the day sun protection actually matters.

The whole year hour by hour: each column is a day, each row an hour, and the color is the modeled clear-sky UV index — the midday peak scaled down as the sun sits lower in the sky. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.

UV falls off far faster than brightness as the sun drops, so even in January the burn window is concentrated in the middle of the day: about 9 hours a day reach index 3 (protection recommended), and 7 hours reach 6 or more. Mornings and late afternoons stay comparatively gentle year round.

JanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AM
UV ≥ 3 (h/day)UV ≥ 6 (h/day)
Jan97
Feb8.56.5
Mar7.55.5
Apr62.5
May40
Jun20
Jul2.50
Aug4.50
Sep6.52.5
Oct7.55
Nov8.56
Dec97
Almanac & agriculture

Growing season

Chance of a frost-free dayReliably frost-free (≥90%)

San Francisco is mild enough that a frost-free day stays more likely than not even in midwinter. Nights are reliably above freezing from about July 17 to July 11 (360 days); outside that window a hard frost is an occasional risk.

0%25%50%75%100%JanFebMarAprMayJunJulAugSepOctNovDecreliably frost-freereliably frost-freeJul 1790%Jul 1190%
Frost-free chance (%)Frost nights
Jan1000
Feb1000
Mar1000
Apr1000
May990
Jun940
Jul910
Aug950
Sep990
Oct1000
Nov1000
Dec1000

Growing degree days

Degree days (base 10°C)Frost-free shaded

Growing degree days tally heat above 10°C: each day adds however many degrees its average temperature runs over that threshold, and cold days add nothing. San Francisco banks about 3,170 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around January.

01,0002,0003,000JanFebMarAprMayJunJulAugSepOctNovDec
Growing degree days (°C·days)
Jan454
Feb381
Mar372
Apr267
May171
Jun79
Jul55
Aug123
Sep194
Oct289
Nov356
Dec429

Solar energy

Average daily shortwave solar energy reaching the ground, banded into brightness zones so the number means something at a glance.

Solar energy is how much sunlight actually reaches the ground each day, measured in kilowatt-hours per square metre (kWh/m²) — the combined effect of how long the sun is up, how high it climbs, and how much cloud gets in the way. It's the raw fuel a solar panel has to work with: for scale, 1 kWh/m² a day is dim and wintry, while 7+ is desert-bright.

San Francisco receives about 4.9 kWh/m² a day of solar energy on average — bright — with a clear seasonal swing between 2.5 and 7.2 kWh/m².

The brighter stretch of the year lasts 6.2 months, from around Sep 14 to Mar 20. The brightest month is December, averaging about 7.2 kWh/m² (intense).

The dimmest month is June, down near 2.6 kWh/m² — roughly 64% less than the December peak.

012345678JanFebMarAprMayJunJulAugSepOctNovDecbrighterdimmerbrighterdimmoderatebrightintenseDec 157.2 kWhJun 162.5 kWh
Solar energy (kWh/m²)Level
Jan7.1Intense
Feb6.2Intense
Mar5.1Bright
Apr3.8Moderate
May2.9Moderate
Jun2.5Moderate
Jul2.9Moderate
Aug3.9Moderate
Sep5.0Bright
Oct5.7Bright
Nov6.8Intense
Dec7.2Intense

Where is San Francisco?

San Francisco sits at 31.4°S, 62.1°W, 120 m above sea level, in Argentina. The nearest listed city is San Jorge, 57 km away.

Topography around San Francisco

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of San Francisco.

Within 3 km, the terrain around San Francisco has only modest variations in elevation — a maximum elevation change of 13 m around an average of 114 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 24 m; within 80 km, only modest variations in elevation — a maximum elevation change of 103 m.

The land around San Francisco is covered by artificial surfaces (50%) and cropland (30%) within 3 km, cropland (94%) within 16 km, and cropland (88%) within 80 km.

3 km
13 m
16 km
24 m
80 km
103 m
treesgrasslandcroplandartificial surfaceswater
Nearby: San Jorge 57 km · Rafaela 60 km · Sunchales 73 km · Las Varillas 78 km · Morteros 80 km · Arroyito 92 km · Gálvez 106 km · Esperanza 109 km

Argentina travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type C / I
220 V · 50 Hz
Prices
≈ 46% of US
price level, 2025
GDP per capita
$14,898
2025
Happiness
6.4 / 10
World Happiness, 2025
Homicide rate
4.5
per 100k, 2023
Road deaths
14.1
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
High
EF EPI 575
Religion
Roman Catholic 63%none 19%Evangelical 15%Jehovah's Witness and Church of Jesus Christ 1%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for San Francisco (-31.425°, -62.084°, elevation 120 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).