National Weather Service Forecast for: Diamond Bar CA
Issued by: National Weather Service Los Angeles/Oxnard, CA
Updated: 1:06 am PST Feb 2, 2026
 
Today

Today: Sunny, with a high near 76. Calm wind becoming southwest around 5 mph in the afternoon.
Sunny
 Tonight

Tonight: Mostly clear, with a low around 55. Calm wind.
Mostly Clear
 Tuesday

Tuesday: Sunny, with a high near 84. Northeast wind around 5 mph becoming calm.
Sunny
 Tuesday
Night
Tuesday Night: Clear, with a low around 58. Northeast wind 5 to 10 mph.
Clear
 Wednesday

Wednesday: Sunny, with a high near 88. Northeast wind around 10 mph, with gusts as high as 15 mph.
Sunny
 Wednesday
Night
Wednesday Night: Mostly clear, with a low around 60.
Mostly Clear
 Thursday

Thursday: Mostly sunny, with a high near 86.
Mostly Sunny
 Thursday
Night
Thursday Night: Partly cloudy, with a low around 56.
Partly Cloudy
 Friday

Friday: Partly sunny, with a high near 75.
Partly Sunny
Hi 76 °F Lo 55 °F Hi 84 °F Lo 58 °F Hi 88 °F Lo 60 °F Hi 86 °F Lo 56 °F Hi 75 °F

Air Quality Alert
 

Today
 
 Sunny, with a high near 76. Calm wind becoming southwest around 5 mph in the afternoon.
Tonight
 
 Mostly clear, with a low around 55. Calm wind.
Tuesday
 
 Sunny, with a high near 84. Northeast wind around 5 mph becoming calm.
Tuesday Night
 
 Clear, with a low around 58. Northeast wind 5 to 10 mph.
Wednesday
 
 Sunny, with a high near 88. Northeast wind around 10 mph, with gusts as high as 15 mph.
Wednesday Night
 
 Mostly clear, with a low around 60.
Thursday
 
 Mostly sunny, with a high near 86.
Thursday Night
 
 Partly cloudy, with a low around 56.
Friday
 
 Partly sunny, with a high near 75.
Friday Night
 
 Partly cloudy, with a low around 53.
Saturday
 
 Sunny, with a high near 77.
Saturday Night
 
 Mostly clear, with a low around 53.
Sunday
 
 Sunny, with a high near 80.

 

Forecast from NOAA-NWS for Diamond Bar CA.