Heat — San Bernardino and Riverside County Valleys - the Inland Empire, California

2025-08-22 · San Bernardino and Riverside County Valleys - the Inland Empire, California

Event narrative

Tied daily record high temperature of 107 at San Jacinto.

Wider weather episode

An upper level high pressure system allowed for a combination of above average temperatures and high humidity to produce an elevated heat risk for inland areas August 20-24. This was locally enhanced by heat bursts produced by shower activity in the coastal and valley areas on the afternoon of August 23.

Source: NOAA Storm Events Database, event_id 1293497. Narrative written by the NWS forecast office that issued the report.