Rialto Weather in September

September in Rialto averages 34°C (93°F) during the day and 17°C (63°F) at night. With only 4.6 mm (0.2 in) of rainfall expected on average, it's a largely dry month.

Rainfall in Rialto in September

Climate statistics over the past 30 years suggest around a single day of rain, with 4.6 mm (0.2 in) average for the month. On the rare occasion it rains, expect a brief, moderate shower rather than a heavy downpour.

Temperature in Rialto in September

September in Rialto brings very high temperatures, with highs of 34°C (93°F) and nights around 17°C (63°F). Sunshine and humidity can make it feel even warmer than the raw temperature suggests. Nights cool down to 17°C (63°F), so a light jacket or extra layer is useful once the sun goes down. On the plus side, the cooler nights make for comfortable sleeping conditions.

Sunshine in Rialto in September

There are approximately 290 hours of sunshine this month, resulting in mostly clear days.

If you prefer dry days with pleasant temperatures, September may not be the ideal month to visit Rialto. Our weather planner can help you explore destinations with more pleasant weather conditions.