Compare the Climate and Weather in Porto and San Francisco

This page lets you compare and contrast the weather and climate in Porto and San Francisco year round.

You can drill down to a specific season, month, and even day by clicking the graphs or using the navigation panel.

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San Francisco
United States

Average High and Low Temperature

Compare the Average High and Low Temperature in Porto and San FranciscoJanFebMarAprMayJunJulAugSepOctNovDec40°F40°F45°F45°F50°F50°F55°F55°F60°F60°F65°F65°F70°F70°F75°F75°F604376565845723942NowNowSan FranciscoSan FranciscoPortoPorto
The daily average high and low air temperature at 2 meters above the ground. The thin dotted lines are the corresponding perceived temperatures.
Porto 56°F58°F61°F63°F67°F72°F75°F75°F73°F68°F62°F57°F
San Francisco 57°F60°F63°F65°F67°F69°F70°F70°F72°F70°F63°F57°F
Porto 43°F44°F46°F49°F53°F57°F59°F59°F57°F54°F48°F45°F
San Francisco 46°F49°F51°F53°F54°F55°F56°F57°F58°F56°F52°F47°F


Average Hourly Temperature in PortoJanFebMarAprMayJunJulAugSepOctNovDec12 AM12 AM4 AM4 AM8 AM8 AM12 PM12 PM4 PM4 PM8 PM8 PM12 AM12 AMNowNowcoldcoldcoldcoldcoolcomfortable

San Francisco

Average Hourly Temperature in San FranciscoJanFebMarAprMayJunJulAugSepOctNovDec12 AM12 AM4 AM4 AM8 AM8 AM12 PM12 PM4 PM4 PM8 PM8 PM12 AM12 AMNowNowcoldcoldcoolcomfortable
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The average hourly temperature, color coded into bands. The shaded overlays indicate night and civil twilight.

Chance of Clearer Skies

Compare the Chance of Clearer Skies in Porto and San FranciscoJanFebMarAprMayJunJulAugSepOctNovDec0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%85439245NowNowSan FranciscoSan FranciscoPortoPorto
The percentage of time the sky is clear, mostly clear, or partly cloudy (i.e., less than 60% of the sky is covered by clouds).
Clearer SkiesJanFebMarAprMayJunJulAugSepOctNovDec
Porto 46%50%52%54%59%69%84%78%64%51%46%44%
San Francisco 47%47%51%58%67%81%90%90%87%72%56%49%

Daily Chance of Precipitation

Compare the Daily Chance of Precipitation in Porto and San FranciscoJanFebMarAprMayJunJulAugSepOctNovDec0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%38531NowNowSan FranciscoSan FranciscoPortoPorto
The percentage of days in which precipitation is observed, excluding trace quantities.
Days of Precip.JanFebMarAprMayJunJulAugSepOctNovDec
Porto 10.7d8.7d8.1d8.9d7.8d4.1d1.7d2.4d5.4d10.5d10.7d10.6d
San Francisco 8.2d8.4d7.5d3.9d2.1d0.7d0.1d0.1d0.7d2.6d6.1d8.5d

Average Monthly Rainfall

Compare the Average Monthly Rainfall in Porto and San FranciscoJanFebMarAprMayJunJulAugSepOctNovDec0 in0 in1 in1 in2 in2 in3 in3 in4 in4 in5 in5 in6 in6 in5.20.43.9NowNowSan FranciscoSan FranciscoPortoPorto
The average rainfall accumulated over the course of a sliding 31-day period centered on the day in question.
Porto 4.5″3.5″2.8″3.1″2.3″1.0″0.4″0.7″2.1″4.5″4.9″5.1″
San Francisco 3.6″3.9″2.7″1.1″0.5″0.1″0.0″0.0″0.2″1.0″2.4″3.7″

Hours of Daylight

Compare the Hours of Daylight in Porto and San FranciscoJanFebMarAprMayJunJulAugSepOctNovDec4 hr4 hr6 hr6 hr8 hr8 hr10 hr10 hr12 hr12 hr14 hr14 hr16 hr16 hr18 hr18 hr20 hr20 hr15.19.2NowNowSan FranciscoSan FranciscoPortoPorto
The number of hours during which the Sun is at least partly above the horizon.
Porto 9.6h10.6h12.0h13.4h14.5h15.1h14.8h13.8h12.4h11.1h9.9h9.3h
San Francisco 9.9h10.8h12.0h13.2h14.2h14.7h14.5h13.6h12.4h11.2h10.1h9.6h

Chance of Muggy Conditions

Compare the Chance of Muggy Conditions in Porto and San FranciscoJanFebMarAprMayJunJulAugSepOctNovDec0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%8NowNowSan FranciscoSan FranciscoPortoPorto
The percentage of time that is muggy, oppressive, or miserable (i.e., a dew point greater than 65°F).
Muggy daysJanFebMarAprMayJunJulAugSepOctNovDec
Porto 0.0d0.0d0.0d0.0d0.0d0.6d1.3d2.2d1.3d0.6d0.1d0.0d
San Francisco 0.0d0.0d0.0d0.0d0.0d0.0d0.0d0.1d0.1d0.0d0.0d0.0d

Average Wind Speed

Compare the Average Wind Speed in Porto and San FranciscoJanFebMarAprMayJunJulAugSepOctNovDec0 mph0 mph1 mph1 mph2 mph2 mph3 mph3 mph4 mph4 mph5 mph5 mph6 mph6 mph7 mph7 mph8 mph8 mph9 mph9 mph10 mph10 mph7. FranciscoSan FranciscoPortoPorto
The average of mean hourly wind speeds at 10 meters above the ground.
Wind Speed (mph)JanFebMarAprMayJunJulAugSepOctNovDec
San Francisco

Average Water Temperature

Compare the Average Water Temperature in Porto and San FranciscoJanFebMarAprMayJunJulAugSepOctNovDec52°F52°F54°F54°F56°F56°F58°F58°F60°F60°F62°F62°F64°F64°F64565853NowNowSan FranciscoSan FranciscoPortoPorto
The daily average wide-area surface water temperature.
Water Temp.JanFebMarAprMayJunJulAugSepOctNovDec
Porto 57°F56°F57°F58°F60°F62°F63°F64°F64°F63°F61°F58°F
San Francisco 53°F53°F54°F53°F53°F54°F56°F57°F58°F57°F56°F54°F

Tourism Score

Compare the Tourism Score in Porto and San FranciscoJanFebMarAprMayJunJulAugSepOctNovDec002244668810108. FranciscoSan FranciscoPortoPorto
The tourism score, which favors clear, rainless days with perceived temperatures between 65°F and 80°F.

Beach/Pool Score

Compare the Beach/Pool Score in Porto and San FranciscoJanFebMarAprMayJunJulAugSepOctNovDec002244668810105.61.6NowNowSan FranciscoSan FranciscoPortoPorto
The beach/pool score, which favors clear, rainless days with perceived temperatures between 75°F and 90°F.

Growing Season

Compare the Growing Season in Porto and San FranciscoJanFebMarAprMayJunJulAugSepOctNovDec0%0%20%20%40%40%60%60%80%80%100%100%NowNowSan FranciscoSan FranciscoPortoPorto
The percentage chance that a given day is within the growing season, defined as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).

Growing Degree Days

Compare the Growing Degree Days in Porto and San FranciscoJanFebMarAprMayJunJulAugSepOctNovDec500°F500°F1,000°F1,000°F1,500°F1,500°F2,000°F2,000°F2,500°F2,500°F3,000°F3,000°F3,500°F3,500°FNowNowSan FranciscoSan FranciscoPortoPorto
The average growing degree days accumulated over the course of the year, where growing degree days are defined as the integral of warmth above a base temperature (50°F in this case).

Average Daily Incident Shortwave Solar Energy

Compare the Average Daily Incident Shortwave Solar Energy in Porto and San FranciscoJanFebMarAprMayJunJulAugSepOctNovDec0 kWh0 kWh1 kWh1 kWh2 kWh2 kWh3 kWh3 kWh4 kWh4 kWh5 kWh5 kWh6 kWh6 kWh7 kWh7 kWh8 kWh8 kWh9 kWh9 kWh7. FranciscoSan FranciscoPortoPorto
The average daily shortwave solar energy reaching the ground per square meter.
Solar Energy (kWh)JanFebMarAprMayJunJulAugSepOctNovDec
San Francisco

This report illustrates the typical weather for Porto and San Francisco year round, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.

The details of the data sources used on this page vary between places and are discussed in detail on each place's dedicated page:


The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.

We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.

We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader.

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