San Jose Climate 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.

	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

												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	-	-	-

Winter = Dec, Jan, and Feb		Spring = Mar, Apr, and May
Summer = Jun, Jul, and Aug.		Fall = Sep, Oct, and Nov