Diamond Bar, CA Weather & Growing Conditions
Today
91°F
Sunny
Sunny, with a high near 91. Southwest wind 0 to 10 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 91°F | Sunny | 0 to 10 mph SW | 0% |
| Tonight | 62°F | Partly Cloudy | 0 to 10 mph SW | 0% |
| Wednesday | 90°F | Sunny | 0 to 10 mph SW | 0% |
| Wednesday Night | 63°F | Mostly Clear | 0 to 10 mph SW | 0% |
| Thursday | 91°F | Sunny | 0 to 10 mph SW | 0% |
| Thursday Night | 63°F | Mostly Clear | 0 to 10 mph SW | 0% |
| Friday | 92°F | Sunny | 0 to 10 mph SW | 0% |
| Friday Night | 63°F | Mostly Clear | 0 to 10 mph SW | 0% |
| Saturday | 90°F | Sunny | 0 to 10 mph SW | 0% |
| Saturday Night | 64°F | Mostly Clear | 0 to 10 mph SW | 0% |
| Sunday | 90°F | Sunny | 0 to 10 mph SW | 0% |
| Sunday Night | 64°F | Mostly Clear | 0 to 10 mph SW | 2% |
| Monday | 89°F | Sunny | 0 to 10 mph SW | 3% |
| Monday Night | 63°F | Mostly Clear | 0 to 10 mph SW | 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 Aug 4, 2026.