Historical weather data, all-time temperature records, and monthly climate averages for San Jacinto, CA. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 4th in San Jacinto typically brings a pleasant 75° high and a cool 45° low — classic spring transitional weather. There's only an 8% chance of rain today, though the date has seen some surprises: a scorching 96° in 1989 and a near-freezing 33° back in 1981.
San Jacinto plays in extremes — the all-time high of 116° on September 3, 1982 puts it firmly in Inland Empire heat territory, while an 18° low on December 8, 1978 proves winter nights here have real bite. Snow is rare but not mythical; the valley once picked up half an inch on November 12, 1985.
San Jacinto peaks in late July, when average highs hit 99°, and bottoms out around Christmas week at a mild 65°. The shoulder seasons are the sweet spot for visitors — April through May and October through November offer highs in the 77–85° range with minimal rain. If you're trying to avoid wet weather, aim for summer; the wettest stretch is late February into early March, averaging 0.69 inches per week.