This report describes the typical weather at the San Francisco International Airport (San Francisco, California, United States) weather station over the course of an average November. It is based on the historical records from 1974 to 2012. Earlier records are either unavailable or unreliable.
San Francisco, California has a mediterranean climate with dry warm summers and mild winters. The area within 25 mi of this station is covered by oceans and seas (48%), built-up areas (16%), grasslands (14%), forests (13%), and shrublands (8%).
The month of November is characterized by falling daily high temperatures, with daily highs decreasing from 66Â°F to 59Â°F over the course of the month, exceeding 73Â°F or dropping below 54Â°F only one day in ten.
Over the course of November, the length of the day is gradually decreasing. From the start to the end of the month, the length of the day decreases by 50 minutes, implying an average day-over-day decrease of 1.7 minutes.
The shortest day of the month is November 30 with 9:45 hours of daylight; the longest day is November 1 with 10:36 hours of daylight.
The earliest sunrise is at 6:38am on November 4; the latest sunset is at 6:11pm on November 1; the latest sunrise is at 7:37am on November 3; the earliest sunset is at 4:51pm on November 30.
Daylight savings time (DST) ends at 1:00am on November 4, 2012, shifting sunrise and sunset to an hour earlier.
The median cloud cover ranges from 45% (partly cloudy) to 57% (partly cloudy). The trend is for the sky to be becoming cloudier with the median cloud cover increasing by 12% from the start to the end of the month.
On November 1, the clearest day of the month, the sky is clear, mostly clear, or partly cloudy 66% of the time, and overcast or mostly cloudy 34% of the time.
On November 30, the cloudiest day of the month, the sky is overcast, mostly cloudy, or partly cloudy 60% of the time, and clear or mostly clear 40% of the time.
The probability that precipitation will be observed at this location varies throughout the month. Precipitation is most likely around November 30, occurring in 34% of days. Precipitation is least likely around November 1, occurring in 25% of days.
Throughout November, the most common forms of precipitation are light rain, moderate rain, drizzle, and heavy rain.
Light rain is the most severe precipitation observed during 44% of those days with precipitation. It is most likely around November 28, when it is observed during 15% of all days.
Moderate rain is the most severe precipitation observed during 32% of those days with precipitation. It is most likely around November 30, when it is observed during 11% of all days.
Drizzle is the most severe precipitation observed during 11% of those days with precipitation. It is most likely around November 10, when it is observed during 4% of all days.
Heavy rain is the most severe precipitation observed during 11% of those days with precipitation. It is most likely around November 30, when it is observed during 4% of all days.
Either snow is exceptionally unlikely to fall at this location in November or this station does not reliably report precipitation types.
The relative humidity typically ranges from 52% (mildly humid) to 92% (very humid) over the course of a typical November, rarely dropping below 31% (comfortable) and reaching as high as 100% (very humid).
The air is driest around November 1, at which time the relative humidity drops below 64% (mildly humid) three days out of four; it is most humid around November 14, rising above 88% (very humid) three days out of four.
Dew point is often a better measure of how comfortable a person will find the weather than relative humidity because it more directly relates to whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid.
Over the course of a typical November, the dew point typically varies from 40Â°F (dry) to 53Â°F (very comfortable) and is rarely below 30Â°F (dry) or above 58Â°F (comfortable).
Over the course of November typical wind speeds vary from 0 mph to 17 mph (calm to moderate breeze), rarely exceeding 24 mph (strong breeze).
The highest average wind speed of 8 mph (gentle breeze) occurs around November 1, at which time the average daily maximum wind speed is 17 mph (moderate breeze).
The lowest average wind speed of 7 mph (light breeze) occurs around November 29, at which time the average daily maximum wind speed is 14 mph (moderate breeze).