San Francisco vs Seattle weather, all year round
San Francisco's average temperature is 2.0°C higher than Seattle's (13.6°C against 11.6°C).
San Francisco gets 31% less rainfall than Seattle (739 mm against 1068 mm).
Best time to visit
San Francisco's most comfortable months are August, September and October. Seattle's are July, August and September. Both score 70 or more out of 100 in June, July, August and September.
San Francisco's most comfortable month is September, Seattle's is July. The least comfortable month is March in San Francisco and January in Seattle.
The lead in comfort score changes hands during the year: Seattle from late June to mid September, then San Francisco from mid September to mid June.
San Francisco's comfort score is 16 points higher than Seattle's (64/100 against 48/100).
Weekly averages over three years.
Temperature
San Francisco's average temperature is 2.0°C higher than Seattle's (13.6°C against 11.6°C).
San Francisco's hottest month is September, Seattle's is July. The coolest month is February in San Francisco and January in Seattle.
The lead in average temperature changes hands during the year: Seattle from late May to mid September, then San Francisco from mid September to late May.
San Francisco's average daytime high is 1.7°C higher than Seattle's (17.3°C against 15.6°C).
San Francisco's average nighttime low is 2.5°C higher than Seattle's (10.7°C against 8.2°C).
Neither city has any days above 30°C (86°F) to speak of.
Seattle gets 19 days below freezing a year. San Francisco gets almost none.
Weekly averages over three years.
Feels like and humidity
San Francisco's average feels-like temperature is 2.1°C higher than Seattle's (11.6°C against 9.5°C).
San Francisco's hottest feeling month is September, Seattle's is August. The coolest feeling month is February for both.
The lead in average feels-like temperature changes hands during the year: Seattle from late May to mid September, then San Francisco from mid September to mid May.
San Francisco and Seattle are about the same for humidity (78% against 77%).
Both cities have their most humid month in December. The driest month is October in San Francisco and July in Seattle.
Neither city has any muggy days to speak of.
Weekly averages over three years.
Rainfall
San Francisco gets 31% less rainfall than Seattle (739 mm against 1068 mm).
San Francisco gets 54% fewer rainy days than Seattle (63 days against 139 days).
San Francisco's wettest month is March, Seattle's is December. The driest month is June in San Francisco and July in Seattle.
Monthly totals, averaged over three years.
Sunshine
San Francisco gets 26% more sunshine than Seattle (3646 h against 2891 h).
San Francisco's sunniest month is May, Seattle's is July. The dullest month is December for both.
The lead in sunshine changes hands during the year: Seattle from mid July to early August, then San Francisco from early August to early July.
Weekly averages over three years.
Wind
San Francisco gets 27% more wind than Seattle (24 km/h against 18 km/h).
San Francisco gets 128% more windy days than Seattle (71 days against 31 days).
San Francisco's windiest month is June, Seattle's is December. The calmest month is December in San Francisco and September in Seattle.
Weekly averages over three years.
Snowfall
Seattle gets 19 cm of snowfall a year. San Francisco gets almost none.
Monthly totals, averaged over three years.
Daylight
San Francisco and Seattle are about the same for daylight (12 h against 12 h).
The lead in daylight changes hands during the year: Seattle from late April to mid October, then San Francisco from mid October to mid April.
Weekly averages over three years.
Averages of daily data from 2023 to 2025. Weather data by Open-Meteo.com (CC BY 4.0).