Historical weather data, all-time temperature records, and monthly climate averages for La Mesa, CA. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 5th in La Mesa typically brings a pleasant 74° high and 50° low — classic early spring comfort. The date has some range in its history though: 1989 saw a scorching 102°, while 1999 bottomed out at 39°. Rain is unlikely, with just a 16% historical chance of any precipitation.
La Mesa plays it mild most of the year, but the extremes tell a different story. The all-time high of 114° hit on September 5, 2020 — a brutal reminder of what inland SoCal heat can do — while Christmas Day 1987 brought a record low of 25°. The wettest single day on record dropped 3.8 inches on December 22, 2010.
La Mesa stays comfortably warm year-round, with monthly highs never dipping below 69° even in late December. Peak heat arrives in late summer — the first week of September averages a 91° high — while late February into early March is your best bet for catching any rain, averaging 0.73 inches that week. If you're avoiding heat, spring and fall sit in the sweet spot around 75–82°.