| National Weather Service Forecast for:
Diamond Bar CA Issued by: National Weather Service Los Angeles/Oxnard, CA |
||||||||||||||||||
| Updated: 3:42 pm PDT Jul 12, 2026 | ||||||||||||||||||
|
Extreme Heat Watch
Heat Advisory
| Tonight |
Partly cloudy, with a low around 67. Southwest wind 5 to 10 mph. |
| Monday |
Partly sunny, with a high near 90. Light southwest wind becoming west southwest 5 to 10 mph in the morning. |
| Monday Night |
Patchy fog after 11pm. Otherwise, mostly cloudy, with a low around 68. Southwest wind 5 to 10 mph becoming light in the evening. |
| Tuesday |
Patchy fog before 11am. Otherwise, cloudy through mid morning, then gradual clearing and hot, with a high near 96. Heat index values as high as 109. Light southwest wind becoming west southwest 5 to 10 mph in the morning. Winds could gust as high as 15 mph. |
| Tuesday Night |
Mostly clear, with a low around 69. Southwest wind 5 to 10 mph becoming light west southwest in the evening. |
| Wednesday |
Sunny and hot, with a high near 101. |
| Wednesday Night |
Mostly clear, with a low around 72. |
| Thursday |
Mostly sunny, with a high near 95. |
| Thursday Night |
Partly cloudy, with a low around 68. |
| Friday |
Mostly sunny, with a high near 89. |
| Friday Night |
A slight chance of showers. Partly cloudy, with a low around 66. |
| Saturday |
A slight chance of showers. Mostly sunny, with a high near 89. |
| Saturday Night |
Mostly clear, with a low around 66. |
| Sunday |
Mostly sunny, with a high near 88. |
Forecast from NOAA-NWS for Diamond Bar CA.
