Historical weather data, all-time temperature records, and monthly climate averages for Tustin, CA. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 4th in Tustin is a mild spring day on average, with highs around 72° and lows near 49°. But the date has a wild range in the record books — from a scorching 98° back in 1989 to a near-freezing 33° in 1945. Rain is unlikely, with only a 16% historical chance of any precipitation.
Tustin has seen some genuine extremes over its 120 years of records — from a brutal 114° in July 2018 to a bitter 16° in January 1989. A single February storm in 1927 dumped 4.69 inches of rain in one day, which still stands as the all-time wettest. Overall, though, this is classic Southern California: the extremes are memorable precisely because they're rare.
Tustin stays remarkably temperate year-round, with average highs ranging from just 68° in early January to a peak of 86° in late August and early September. Even the 'cool' season barely dips — December through February averages in the upper 60s. If you're worried about rain, aim to visit outside of February, when precipitation is at its highest at around 0.76 inches per week.