Like most of the San Francisco Bay Area, Sunnyvale has a Mediterranean climate, with mild, moist winters and comfortably warm, very dry summers just right for sports like soccer, football, and basketball.
Average day time summer temperatures are in the high 70s, and during the winter, average day time high temperatures rarely stay below 50 °F (10 °C).
Climate data for Sunnyvale, California |
Month |
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
Year |
Record high °F (°C) |
75
(23.9) |
84
(28.9) |
85
(29.4) |
94
(34.4) |
100
(37.8) |
107
(41.7) |
105
(40.6) |
101
(38.3) |
105
(40.6) |
100
(37.8) |
89
(31.7) |
75
(23.9) |
107 |
Average high °F (°C) |
58
(14.4) |
62
(16.7) |
64
(17.8) |
69
(20.6) |
73
(22.8) |
77
(25) |
79
(26.1) |
79
(26.1) |
78
(25.6) |
73
(22.8) |
64
(17.8) |
58
(14.4) |
69.5
(20.83) |
Average low °F (°C) |
40
(4.4) |
43
(6.1) |
46
(7.8) |
47
(8.3) |
51
(10.6) |
55
(12.8) |
57
(13.9) |
57
(13.9) |
55
(12.8) |
50
(10) |
44
(6.7) |
39
(3.9) |
48.7
(9.26) |
Record low °F (°C) |
21
(-6.1) |
24
(-4.4) |
22
(-5.6) |
31
(-0.6) |
33
(0.6) |
40
(4.4) |
41
(5) |
44
(6.7) |
41
(5) |
34
(1.1) |
15
(-9.4) |
20
(-6.7) |
15 |
Precipitation inches (mm) |
3.24
(82.3) |
3.18
(80.8) |
2.65
(67.3) |
0.89
(22.6) |
0.35
(8.9) |
0.11
(2.8) |
0.03
(0.8) |
0.08
(2) |
0.19
(4.8) |
0.85
(21.6) |
1.83
(46.5) |
2.31
(58.7) |
15.71
(399) |
Source: National Weather Service |
On May 4, 1998, during an unusually strong thunderstorm, Sunnyvale and its neighbor Los Altos were hit by two tornadoes of nearly F2 intensity, causing upwards of $4 million in property damage. No serious injuries were reported. Tornadoes are not common in the San Francisco Bay Area, and these were particularly unique because they exhibited anticyclonic rotation. This was the first time that weather radar data of such high quality had been collected for an anticyclonic supercell thunderstorm with tornadoes. Smaller tornadoes are not completely unheard of in the area, but tornadoes are generally rare here. Sunnyvale experienced another small tornado at the Lockheed-Martin facility at Moffett Federal Airfield two months prior to this one.
On January 21, 1962, and on February 5, 1976, measurable snowfall occurred in Sunnyvale and most of the San Francisco Bay Area.
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