Fontana Weather Forecast
- 72
- 102
Hot
- 71
- 100
Hot
- 71
- 100
Hot
- 71
- 98
Hot
- 71
- 98
Hot
- 71
- 98
Hot
Today 19 Aug San Bernardino and Riverside County Valleys-The Inland Empire
Mostly sunny. Highs 99 to 105. Light Winds becoming west 10 to 15 Mph with Gusts to 25 Mph this afternoon.
Tonight 19 Aug San Bernardino and Riverside County Valleys-The Inland Empire
Mostly clear. Lows 66 to 72. Areas of Winds west to 10 Mph this evening becoming light.
Fontana Temperature Statistics
August Temperature
Ontario International Airport (8.1 miles)
Lowest 15 August, 2026
65.6 °FAverage August
82.7 °FHighest 1 August, 2026
102.7 °F
Climate (2021–2026)
Ontario International Airport (8.1 miles)
Average Low 2021–2026
55.8 °FAverage 2021–2026
67.1 °FAverage High 2021–2026
79.3 °F