Diamond Bar, CA Weather & Growing Conditions
Tonight
53°F
Mostly Clear
Mostly clear, with a low around 53. Northwest wind 0 to 5 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 53°F | Mostly Clear | 0 to 5 mph NW | 0% |
| Wednesday | 72°F | Sunny | 0 to 5 mph SSW | 0% |
| Wednesday Night | 54°F | Mostly Clear | 5 mph NNW | 0% |
| Thursday | 77°F | Sunny | 0 to 10 mph NNE | 0% |
| Thursday Night | 56°F | Mostly Clear | 0 to 10 mph N | 0% |
| Friday | 79°F | Sunny | 0 to 10 mph NE | 0% |
| Friday Night | 57°F | Clear | 0 to 15 mph NNE | 0% |
| Saturday | 83°F | Sunny | 0 to 10 mph NE | 0% |
| Saturday Night | 60°F | Clear | 0 to 15 mph NNE | 0% |
| Sunday | 84°F | Sunny | 0 to 10 mph NE | 0% |
| Sunday Night | 61°F | Partly Cloudy | 0 to 15 mph NNE | 0% |
| Monday | 81°F | Mostly Sunny | 0 to 5 mph ESE | 0% |
| Monday Night | 60°F | Partly Cloudy | 0 to 5 mph ENE | 1% |
| Tuesday | 79°F | Mostly Sunny | 0 to 5 mph S | 2% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Diamond Bar, CA
Last spring frost
Jan 8
First fall frost
Dec 28
Growing season
354 days
Hardiness zone
10a
Explore more for Diamond Bar, CA: full frost dates · planting calendar · California frost dates
Climate data from the nearest NOAA station, Pomona/Fairplex, Ca (7.2 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.