Historical weather data, all-time temperature records, and monthly climate averages for San Bruno, CA. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 5th in San Bruno runs mild and mostly dry — expect a high near 63° and a low around 48°, with just a 1-in-4 chance of rain. The date has seen some wild swings over 80 years of records, from a scorching 84° in 1989 down to a frigid 39° overnight in 1975.
San Bruno's weather is defined by its extremes: the thermometer has hit 105° (June 2000) and cratered to 24° (December 1972), a 81-degree spread that captures the Bay Area's occasional bouts of drama. A single January day in 1982 dropped 5.59 inches of rain, and the city has even seen 1.5 inches of snow, back in January 1962.
San Bruno stays mild year-round, but late summer is the sweet spot — the warmest week runs August 27 through September 2, with average highs of 74°. If you hate cold, avoid early January, when highs dip to just 55°. Rain is almost exclusively a winter affair, peaking in the final week of December at over an inch on average.