Weather and climate in Pleasanton, CA

Local time 4:08 am PST 37.66° N, 121.87° W
Best for stargazingSep, Oct, NovMost clear, dark hours
Warmest monthAugustAverage high 84°F
Coolest monthJanuaryAverage low 38°F
Wettest monthDecember4.5 in on average

What the weather is like in Pleasanton

The warmest month in Pleasanton is August, with average highs of 84°F. The coolest is January, when nights average 38°F. About 20.1 in of rain and snow falls in a typical year, most in December and least in July.

Skies are clearest in July (12% average cloud cover) and cloudiest in December (54%). Combining cloud with the length of truly dark nights, September, October, November offer the most clear, dark hours for stargazing.

Clear, dark hours per night

Hours of full astronomical darkness in mid-month, multiplied by the average share of clear sky. A rough guide to how much good observing time a typical night offers.

Monthly averages

MonthHighLowPrecipitationCloud coverHumidityWindDark hours
January 56°F 38°F 3.5 in 54% 84% 4 mph 11.1 h
February 58°F 39°F 3.6 in 50% 83% 4 mph 10.2 h
March 61°F 41°F 3.0 in 48% 82% 4 mph 9.1 h
April 64°F 42°F 1.6 in 41% 78% 5 mph 7.7 h
May 70°F 46°F 0.6 in 29% 73% 6 mph 6.3 h
June 78°F 49°F 0.2 in 16% 66% 6 mph 5.4 h
July 83°F 51°F 0.0 in 12% 62% 6 mph 5.9 h
August 84°F 51°F 0.0 in 12% 63% 6 mph 7.2 h
September 83°F 51°F 0.1 in 14% 60% 5 mph 8.6 h
October 75°F 48°F 1.0 in 26% 63% 4 mph 9.9 h
November 64°F 42°F 2.1 in 41% 73% 4 mph 10.9 h
December 56°F 38°F 4.5 in 54% 81% 4 mph 11.3 h

Climate nearby

Climate averages: NASA POWER, 2001–2025, for the grid area around 37.50, -121.88 (about 50 km across). High and low temperatures are estimated from the monthly mean and the average daily range. Hills, coasts and cities can differ from the area average. Sources and methods.