Diamond Bar Weather in September

Diamond Bar in September averages 32°C (90°F) during the day and 17°C (63°F) at night. Minimal rainfall is typical for this time of year.

Rainfall in Diamond Bar in September

Historically, approximately a single day this month are expected to have rain, averaging 4.9 mm (0.2 in). Any rain that does arrive is likely to be fairly light and short-lived.

Temperature in Diamond Bar in September

The excellent temperature in Diamond Bar in September makes it a solid month to visit, with 32°C (90°F) during the day and 17°C (63°F) at night. Sunshine and humidity can make it feel even warmer than the raw temperature suggests. Nights drop to around 17°C (63°F), which is noticeably cooler than the daytime. A light jacket for the evening is a sensible addition, and the cool nights tend to make sleeping comfortable.

Sunshine in Diamond Bar in September

Expect sunny days throughout the month, with an estimated 290 hours of sunshine. This makes it a pleasant time to visit Diamond Bar.

Should you favor a climate that's both dry and comfortably warm, January, February, March, April, May, October and November typically offer the most agreeable circumstances. If you're seeking pleasant, dry and sunny weather somewhere else in the world, our weather planner can help you explore other options.