Diamond Bar, CA Weather & Climate Normals
Diamond Bar's real weather, in one number
Diamond Bar, CA scores 76/100 on this site's reading of NOAA's own 30-year normals: mild with real seasons. A solid stretch of comfortable months alongside a noticeable but not extreme summer or winter. 9 of the year's 12 months average between 55 and 75°F, the range this site counts as mild.
Diamond Bar's hottest and coldest months
Diamond Bar's hottest month is Aug, averaging 78°F; its coldest is Dec, averaging 54°F, a 23.4°F swing across the year, a middling gap by national standards.
Rain and snow in Diamond Bar
Diamond Bar averages 14.47in of precipitation a year across roughly 31 days with measurable rain or snow, and 0in of snow a year.
Where Diamond Bar ranks
Diamond Bar ranks 193 of 4876 US cities in this dataset for comfort score, and 193 of 429 within CA. About 52,292 people live there.
If you need tomorrow's forecast, not the 30-year average
Everything above is a 30-year average from POMONA/FAIRPLEX, CA US, 6.3 miles from Diamond Bar, not a prediction for any specific day.
More on how this is worked out
How the comfort score is calculated · Why some cities show no snow or rain figure