Fontana averages 90 days a year above 90°F, with February the wettest month at 3.07 in of normal rain. The hottest day on record was 118°F on Sep 5, 2020; the coldest, 25°F on Jan 14, 2007. The single biggest 24-hour rain event recorded was 3.62 in on Feb 5, 2024.
Climate and Average Weather Year Round in Fontana
Year-round temperature
In Fontana, the warmest months are June through September, with average daily highs between 86°F and 95°F. The coldest stretch runs December through February, with highs between 67°F and 68°F and overnight lows reaching 44°F.
Rainfall through the year
Rainfall in Fontana averages 1.0 in per month over the long run. February is the wettest at 3.1 in, while June is the driest at 0.0 in.
Days at 90 °F or hotter
Fontana averages 90.0 days per year at 90 °F or hotter. The hottest year on record saw 125 such days (2008); the coolest just 13 (2026).
Precipitation this year
As of May 28, Fontana has received 5.0 in of precipitation this year — 40% below the long-term normal for this point in the year (8.3 in).