How extreme does Millbrae's weather get?

The hottest, coldest, wettest and snowiest days Millbrae has recorded — the outer limits of what its weather can do, and how far they sit beyond a normal day.

Based on 50+ years of daily weather observations (1971–present), from the San Francisco Intl Ap station 3 km away. Updated through May 2026 — an all-time extreme only changes when a more extreme day actually occurs, so some dates are old. That is normal, not stale data.

The four kinds of extreme

The hottest, coldest, wettest and snowiest single days Millbrae has recorded — each shown against what a normal day that time of year looks like.

🔥 Hottest day

105°F Jul 17, 1988

That is about 32°F hotter than a normal July afternoon in Millbrae (typical high near 73°F).

The three most extreme on record

1 105°F Jul 17, 1988

2 105°F Jun 14, 2000

3 104°F Sep 1, 2017

❄️ Coldest night

24°F Dec 9, 1972

About 21°F colder than a normal December night in Millbrae (typical low near 45°F).

The three most extreme on record

1 24°F Dec 9, 1972

2 26°F Dec 11, 1972

3 27°F Dec 22, 1990

🌧️ Most rain in one day

5.59 in Jan 4, 1982

More rain in a single day than Millbrae usually gets in the whole month of January (typical January total about 3.9 in).

The three most extreme on record

1 5.59 in Jan 4, 1982

2 4.02 in Oct 24, 2021

3 3.67 in Dec 31, 2022

How hot and cold it gets, month by month

The shaded band is the normal range of daily temperatures for each month. The dots show the most extreme it has ever been — so you can see how far beyond a normal day the records really sit.

normal range of daily temperatureshottest ever recordedcoldest ever recorded

Millbrae's record heat sits well above even a hot day for the season — July's 105°F is about 32°F beyond a normal hot afternoon. Its record cold is just as far below a normal winter night — the dots mark how rare each extreme really is.

In plain terms

In a normal year, Millbrae's warmest days reach the mid-70s°F and its coldest nights drop to the mid-40s°F. But across the record it has gone as high as 105°F and as low as 24°F. A single day has delivered over 6 inches of rain. Those are the outer edges worth knowing if you are moving here, planning a trip, or thinking about a house.

Methodology & sources

Temperature & precipitation — the official 1991–2020 climate normals from NOAA's U.S. Climate Normals, measured at San Francisco Intl AP (NOAA GHCN station USW00023234), about 3 km from the city centre.

How we build these numbers →

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