The highest day temperature in September 2025 was 112°F. The lowest night temperature was 74°F. The average values for day and night temperatures during September were 102.3°F и 83.0°F respectivly.

Most of the days in September are sunny but you can also expect cloudy and gloomy days.

Precipitation total in September for San Luis Rio Colorado is 0.1 in. This value is relatively stable throughout the year.

The average wind speed in September is 7.3 mph. It makes September one of the most windless months of the year for San Luis Rio Colorado.

We are using day length and cloud cover information for each day of the month to calculate averages for this chart. Average sunny hours for San Luis Rio Colorado in September is 11.2 hours.