San Jose, California Records and Averages

San Jose's latitude and location on the west coast of North America place the city in a Mediterranean type climate. This classification is mainly identified by sharply contrasting wet and dry seasons. The wet season runs from November through March. 82% of the yearly precipitation total falls within this period. Rainfall is sparse from May through October. Rain during the summer months of June, July and August normally totals only 0.20". Wet seasons are cool, but mild. Dry season weather is very consistent, with warm sunny days. Snow is extremely rare in San Jose, with only a handful of well documented instances in over 100 years. Amounts are usually a trace and have never exceeded one inch.

Mid-summer high temperatures, assuming a weak to moderate onshore flow pattern, normally range from 80 to 85 degrees. Lows are consistently between 55 and 60. Afternoon high temperatures are tempered by the sea breeze off the bay. Offshore flow occurs when high pressure at the surface builds over the Great Basin province, with lower pressure off the coast. During offshore flow, all marine influence disappears and temperatures can soar to 100 degrees or more during the dry season. These events occur during any season, but are most common in Fall and secondarily in Spring.

Dry season winds are nearly calm every day during the time period of an hour or two after sunset to around midday . Then, almost like clockwork, a northwest sea breeze of 10 to 15 knots will develop in the afternoon.

Temperatures during mid-winter are generally temperate with highs between 55 and 60 degrees during the day, and around 40 at night. Overnight low temperatures can vary widely during a calm, clear winter night. The bay flats are milder because of the modifying influence of the bay waters and the urban heat island effect near downtown. Wintertime lows in the area average between 40 and 45 degrees. 

Temperature + Precipitation 

  Monthly Averages Daily Extremes Monthly Extremes  
Temperatures
 in F
Max. Min. Avg High Date of 
daily extreme
 high
Low Date of
daily extreme
low
Highest
Avg
Year Lowest
Avg
Year
January 58.0 40.9 49.4 79 08/1962 18 06/1894 55.8 2003 42.3 1937
February 61.9 43.5 52.7 81 26/1986 24 11/1894 59.0 1963 45.7 1894
March 65.4 45.2 55.3 87 11/2005 25 15/1895 61.5 2004 47.4 1897
April 69.5 46.8 58.2 95 09/1989 26 05/1895 63.9 1989 50.9 1967
May 74.3 50.5 62.4 101 27/1984 32 16/1894 70.6 2001 57.2 1896
June 79.1 53.8 66.4 109 14/2000 33 19/1893 72.2 1981 58.9 1893
July 81.8 56.0 68.9 108 07/1905 40 24/1893 73.6 1996 63.4 1893
August 81.4 56.1 68.7 105 01/1993 39 26/1893 74.4 1998 63.3 1893
September 80.4 55.2 67.8 106 07/1904 35 30/1893 72.9 1997 58.8 1893
October 74.3 51.2 62.8 101 05/1987 30 18/1893 67.2 1992 54.7 1893
November 65.2 45.3 55.3 85 03/1950 21 16/1976 60.7 1950 48.3 1896
December 58.4 41.4 49.9 79 12/1958 19 22/1990 55.7 1958 43.9 1990
Annual 70.8 48.8 59.8 109 2000/06/14 18 1894/01/06 63.0 1997 54.4 1893
 
Winter 59.4 41.9 50.7 81 1986/02/26 18 1894/01/06 54.4 1996 46.0 1949  
Spring 69.8 47.5 58.6 101 1984/05/27 25 1895/03/15 63.8 1997 53.7 1894
Summer 80.7 55.3 68.0 109 2000/06/14 33 1893/06/19 72.1 1996 61.8 1893
Fall 73.3 50.6 62.0 106 1904/09/07 21 1976/11/16 65.0 1995 55.0 1893

Precipitation

    Total Snowfall
  Avg. High Year Low Year 1 Day Max. >=
0.01 in.
>=
0.10 in.
>=
0.50 in.
>=
1.00 in.
Mean High Year
  in. in. - in. - in. dd/yyyy
or
yyyymmdd
# Days # Days # Days # Days in. in. -
January 2.93 8.66 1995 0.17 1984 3.95 14/1911 10 6 2 1 - - -
February 2.71 10.23 1998 0.02 1953 2.23 03/1998 10 6 2 0 0.0 0.5 1976
March 2.29 6.85 1995 0.00 1934 2.79 21/1937 9 6 1 0 0.0 0.1 1969
April 1.21 4.55 2006 0.00 1949 1.46 28/1983 6 3 1 0 - - -
May 0.45 2.38 1990 0.00 1935 1.62 27/1990 3 1 0 0 - - -
June 0.08 0.84 1995 0.00 1893 0.79 16/1995 1 0 0 0 - - -
July 0.02 0.75 1980 0.00 1893 0.75 02/1980 0 0 0 0 - - -
August 0.07 1.96 1968 0.00 1893 1.92 21/1968 0 0 0 0 - - -
September 0.20 2.04 1959 0.00 1893 2.00 18/1959 1 1 0 0 - - -
October 0.77 4.59 1962 0.00 1954 3.22 13/1962 3 2 0 0 - - -
November 1.50 6.18 1970 0.00 1956 2.42 29/1970 6 4 1 0 - - -
December 2.44 9.26 1955 0.04 1989 2.60 04/1915 9 5 2 0 - - -
 
Annual 14.65 32.57 1983 6.12 1953 3.95 19110114 59 34 9 2 0.0 0.5 1976
 
Winter 8.07 16.89 1998 1.84 1976 3.95 19110114 28 18 5 1 0.0 0.5 1976
Spring 3.94 11.55 2006 0.19 2008 2.79 19370321 18 10 2 0 0.0 0.1 1969
Summer 0.18 1.96 1968 0.00 1893 1.92 19680821 1 1 0 0 - - -
Fall 2.47 8.27 1972 0.05 1995 3.22 19621013 11 6 2 0 - - -
California averages and extremes in precipitation and temperature and Top 10 U.S climate extremes.
Winter = Dec, Jan, and Feb Spring = Mar, Apr, and May
Summer = Jun, Jul, and Aug. Fall = Sep, Oct, and Nov
Data period is 1893 - 2010, Source: Western Regional Climate Center