National Weather Service Forecast for: Diamond Bar CA
Issued by: National Weather Service Los Angeles/Oxnard, CA
Updated: 2:50 pm PDT May 26, 2026
 
This
Afternoon
This Afternoon: Mostly cloudy, with a high near 67. South wind around 10 mph, with gusts as high as 15 mph.
Mostly Cloudy
 Tonight

Tonight: Mostly cloudy, with a low around 55. South southwest wind around 10 mph, with gusts as high as 15 mph.
Mostly Cloudy
 Wednesday

Wednesday: A 20 percent chance of showers. Cloudy, then gradually becoming mostly sunny, with a high near 65. South southwest wind 5 to 10 mph.
Slight Chance
Showers
 Wednesday
Night
Wednesday Night: A 20 percent chance of showers. Increasing clouds, with a low around 54. Southwest wind 5 to 10 mph becoming light after midnight. Winds could gust as high as 15 mph.
Slight Chance
Showers
 Thursday

Thursday: Partly sunny, with a high near 67. Light and variable wind becoming southwest 5 to 10 mph in the afternoon. Winds could gust as high as 15 mph.
Partly Sunny
 Thursday
Night
Thursday Night: Partly cloudy, with a low around 55.
Partly Cloudy
 Friday

Friday: Sunny, with a high near 71.
Sunny
 Friday
Night
Friday Night: Mostly clear, with a low around 53.
Mostly Clear
 Saturday

Saturday: Sunny, with a high near 75.
Sunny
Hi 67 °F Lo 55 °F Hi 65 °F Lo 54 °F Hi 67 °F Lo 55 °F Hi 71 °F Lo 53 °F Hi 75 °F

 

This Afternoon
 
 Mostly cloudy, with a high near 67. South wind around 10 mph, with gusts as high as 15 mph.
Tonight
 
 Mostly cloudy, with a low around 55. South southwest wind around 10 mph, with gusts as high as 15 mph.
Wednesday
 
 A 20 percent chance of showers. Cloudy, then gradually becoming mostly sunny, with a high near 65. South southwest wind 5 to 10 mph.
Wednesday Night
 
 A 20 percent chance of showers. Increasing clouds, with a low around 54. Southwest wind 5 to 10 mph becoming light after midnight. Winds could gust as high as 15 mph.
Thursday
 
 Partly sunny, with a high near 67. Light and variable wind becoming southwest 5 to 10 mph in the afternoon. Winds could gust as high as 15 mph.
Thursday Night
 
 Partly cloudy, with a low around 55.
Friday
 
 Sunny, with a high near 71.
Friday Night
 
 Mostly clear, with a low around 53.
Saturday
 
 Sunny, with a high near 75.
Saturday Night
 
 Clear, with a low around 55.
Sunday
 
 Sunny, with a high near 80.
Sunday Night
 
 Clear, with a low around 57.
Monday
 
 Sunny, with a high near 82.

 

Forecast from NOAA-NWS for Diamond Bar CA.