Monday, October 19, 2026 · Hour-by-hour forecast updated 12:12 AM PDT
65°F and clear at peak. Wind 5 mph from the ENE, dew point 36°F.
Running in Fontana peaks twice a year — April (FitScore 96) and November (96) — with typical morning lows of 51°F and 50°F respectively. There is no truly bad month here — even July, the weakest, averages a FitScore of 82. That makes Fontana one of the best year-round running cities in the country — #17 of 200, with an annual FitScore of 91 against a national median of 74.
Based on 2015–2024 daily weather history (Open-Meteo ERA5), scored against 200 U.S. cities. Monthly FitScore reflects each day’s best running window.
FitCast texts you tomorrow's hour-by-hour forecast every evening so you know exactly what to expect before your alarm goes off.
Based on today's FitScore analysis, the best time to run is 5 AM–10 AM with a peak FitScore of 99/100. Check the hourly breakdown above for detailed conditions throughout the day.
The best months for running in Fontana are April, November, and May, with average FitScores of 96, 96, and 95 based on a decade of daily weather history. The most challenging is July (FitScore 82).
Historically, October in Fontana averages a FitScore of 94/100 — excellent running weather — with highs around 83°F, lows around 58°F, dew points near 41°F, and 2.2 days of measurable rain. That's above the national median of 86 for October.
FitScore rates each hour from 0–100 for outdoor exercise based on temperature, humidity, dew point, wind, precipitation probability, UV index, and air quality. Higher scores mean better conditions.