Historical weather data, all-time temperature records, and monthly climate averages for Fairfield, CA. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 5 in Fairfield typically delivers a mild spring day, with highs averaging 70° and lows around 46°. There's only a 20% chance of rain, though this date has seen a full 50-degree swing in its history — from a 35° freeze in 2010 to an 85° scorcher back in 1985.
Fairfield plays for keeps on the extremes. Sitting in the Carquinez Strait corridor, it hit a brutal 114° in July 2006 and bottomed out at 15° on Christmas Day 2011 — and it even managed 1.5 inches of snow in December 1988, which is as rare as it sounds for the Central Valley's edge.
Summer is long and hot here, with highs hovering around 89-90° from July through August — peak heat lands the week of July 9-15. If you're dodging rain, avoid mid-February, the wettest stretch of the year, and plan around the fact that truly cool weather only settles in between December and January, when highs dip to the mid-50s.