The highest day temperature in September 2025 was 90°F. The lowest night temperature was 44°F. The average values for day and night temperatures during September were 79.9°F и 60.7°F respectivly.

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

Precipitation total in September for Frederick is 1.0 in.

The average wind speed in September is 6.0 mph. It makes September one of the most windless months of the year for Frederick.

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 Frederick in September is 7.5 hours.