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Weather in Diamond Bar, CA · National Weather Service + NOAA

It hardly ever freezes in Diamond Bar

Diamond Bar has warm winters and warm summers, with very little rain. A typical July afternoon reaches 89°, a January night drops to 45°, and snow is almost unheard of. Normal November highs come to 74°, and lows to 49°.

Winter 68°/45°Spring 74°/51°Summer 88°/61°Fall 81°/56°
Right now
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Sunrise 6:11 am · sunset 4:57 pm

Getting the latest forecast from the National Weather Service…

What stands out about Diamond Bar’s weather

Read from 30 years of NOAA records. Each one opens the full story on the Climate page.

Climate →
It hardly ever freezesOnly 65% of years see a night at 32° or below.Snow is rareNo measurable snow in a normal year.Warming faster than mostThe last 30 years averaged 2.7° warmer than the 1900s, a bigger shift than 100% of U.S. towns.A dry climateJust 15 inches of rain and melted snow a year, less than 94% of U.S. towns.
A normal year

Where today sits in Diamond Bar’s year

Typical highs and lows month by month, from 30 years of NOAA records.

Full climate →
Winter
68° / 45°
Snow is rare
Spring
74° / 51°
Frost is rare by spring
Summer
88° / 61°
71 days reach 90° in a normal year
Fall now
81° / 56°
Mild well into the fall
Best months to be outside
JanFebMarAprMayJunOctNovDec
Highs of 62–84° and lows of 40° or more
How much snow does Diamond Bar get?Almost none.When is it wettest?February, with 4.0 inches.Is it warmer than it used to be?+2.7° vs. the 20th century.

Weather talk

Road reports, first frosts and storm memories from neighbors in Diamond Bar.

Town Square →
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Forecast, conditions and alerts: National Weather Service. Climate: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000. Temperatures and rainfall come from NOAA’s gridded normals for Diamond Bar itself (about a 3-mile square). Snow, frost dates and day counts: the NOAA station at Covina City Yard Fc387b, CA (7 mi, snow) and Pomona/fairplex, CA (6 mi, frost, heat and degree days). Sunrise and sunset are calculated from the town’s position. Normals are 30-year averages, not a forecast.