The highest day temperature in September 2025 was 76°F. The lowest night temperature was 47°F. The average values for day and night temperatures during September were 64.4°F и 58.5°F respectivly.

The average sea surface temperature in September 2025 for Rio Grande was 64.1°F. The maximum and minimum values were 60.2°F and 69.0°F respectively.

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

Precipitation total in September for Rio Grande is 1.9 in. It makes september one of the most rainy months of the year.

The average wind speed in September is 11.8 mph. This value is relatively stable throughout the year.

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 Rio Grande in September is 5.6 hours.