September weather forecast
Frederick, CO

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Weather in September

The first month of the autumn, September, is still a warm month in Frederick, Colorado, with temperature in the range of an average high of 80.1°F (26.7°C) and an average low of 53.4°F (11.9°C).

Temperature

September witnesses a gentle descent in average high-temperature, descending from August's tropical 88.2°F (31.2°C) to a moderately hot 80.1°F (26.7°C). Frederick, in September, experiences a marked contrast from daytime zeniths to a steady average low-temperature of 53.4°F (11.9°C).

Humidity

The average relative humidity in September in Frederick, Colorado, is 41%.

Rainfall

In Frederick, in September, during 7.5 rainfall days, 0.55" (14mm) of precipitation is typically accumulated. Throughout the year, in Frederick, there are 87 rainfall days, and 9.88" (251mm) of precipitation is accumulated.

Snowfall

June through September are months without snowfall in Frederick.

Daylight

In Frederick, the average length of the day in September is 12h and 26min.
On the first day of the month, sunrise is at 6:28 am and sunset at 7:30 pm. On the last day of September, in Frederick, sunrise is at 6:55 am and sunset at 6:43 pm MDT.

Sunshine

In September, the average sunshine in Frederick, Colorado, is 10.9h.

UV index

In September, the average daily maximum UV index is 4. A UV Index value of 3 to 5 symbolizes a medium vulnerability from unsafe exposure to UV radiation for the ordinary person.
Note: In September, an average UV index of 4 transforms into the following instructions:
Heed the precautions - Protecting the skin and eyes from damage is compulsory. The most potent solar radiation is around mid-day, so one should minimize exposure to direct sunlight during this period. Stay sun-safe with clothing that is both closely woven and worn loosely. Be alert! Nearly double the UV rays from the Sun can be reflected by snow.
Updated: Feb 10, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the usual temperature for Frederick in September?

In September, the average high-temperature and low-temperature are 80.1°F (26.7°C) and 53.4°F (11.9°C) respectively. The average heat index (a.k.a. 'real feel', 'apparent temperature'), which takes the relative humidity and factors it into the air temperature reading, in August is calculated to be 87.8°F (31°C).

What is the average humidity in September in Frederick?

In Frederick, the average relative humidity in September is 41%.

How much does it rain in Frederick in September?

In Frederick, Colorado, in September, it is raining for 7.5 days, with typically 0.55" (14mm) of accumulated precipitation.

When it does not snow in Frederick?

June through September are months without snowfall in Frederick.

Does it snow in Frederick in September?

In Frederick, in September, it doesn't snow. In October, it regularly snows.

How many hours of daylight does Frederick have in September?

In Frederick, Colorado, the average day length in September is 12h and 26min.

When are sunrise and sunset in September in Frederick?

In September, on the first day of the month, sunrise is at 6:28 am and sunset at 7:30 pm. On the last day of the month, in Frederick, sunrise is at 6:55 am and sunset at 6:43 pm MDT.

How many hours of sunshine does Frederick have in September?

In September, the average sunshine duration in Frederick, Colorado, is 10.9h.

What is the UV index reading in September in Frederick?

The average daily maximum UV index in September in Frederick, Colorado, is 4. A UV Index reading of 3 to 5 represents a medium hazard to health from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Frederick, CO

Average temperature in September - Frederick, CO
  • Average high temperature in September: 80.1°F

The warmest month (with the highest average high temperature) is July (89.2°F).
The month with the lowest average high temperature is December (40.8°F).

  • Average low temperature in September: 53.4°F

The month with the highest average low temperature is July (61.5°F).
The coldest month (with the lowest average low temperature) is December (21°F).

Average pressure in September
Frederick, CO

Average pressure in September - Frederick, CO
  • Average pressure in September: 30"Hg

The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).

Average wind speed in September
Frederick, CO

Average wind speed in September - Frederick, CO
  • Average wind speed in September: 5.9mph

The windiest month (with the highest average wind speed) is April (7mph).
The calmest month (with the lowest average wind speed) is December (5.7mph).

Average humidity in September
Frederick, CO

Average humidity in September - Frederick, CO
  • Average humidity in September: 41%

The month with the highest relative humidity is February (64%).
The month with the lowest relative humidity is August (40%).

Average rainfall in September
Frederick, CO

Average rainfall in September - Frederick, CO
  • Average rainfall in September: 0.55"

The wettest month (with the highest rainfall) is May (1.69").
The driest months (with the least rainfall) are January and December (0.35").

Average rainfall days in September
Frederick, CO

Average rainfall days in September - Frederick, CO
  • Average rainfall days in September: 7.5 days

The months with the highest number of rainy days are May and July (12.3 days).
The months with the least rainy days are January and December (3 days).

Average snowfall in September
Frederick, CO

Average snowfall in September - Frederick, CO
  • Average snowfall in September: 0"

The month with the highest snowfall is April (4.45").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in September
Frederick, CO

Average snowfall days in September - Frederick, CO
  • Average snowfall days in September: 0.1 days

The month with the highest number of snowfall days is February (7.8 days).
The months with the least snowfall days are June, July and August (0 days).

Average daylight in September /
Average sunshine in September
Frederick, CO

Average daylight in September / Average sunshine in September - Frederick, CO
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).

  • Average sunshine in September: 10h and 5min

The months with the most sunshine are June and July (Average sunshine: 11h and 48min).
The month with the least sunshine is February (Average sunshine: 6h and 42min).

Average sunshine days in September
Frederick, CO

Average sunshine days in September - Frederick, CO
  • Average sunshine days in September: 18.5 days

The month with the most sunshine days is December (24.5 days).
The month with the least sunshine days is July (12.8 days).

Average UV index in September
Frederick, CO

Average UV index in September - Frederick, CO
  • Average UV index in September: 4

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).

Average cloud cover in September
Frederick, CO

Average cloud cover in September - Frederick, CO
  • Average cloud cover in September: 15

The month with the most cloud cover is April (Cloud cover 27).
The month with the least cloud cover is September (Cloud cover 15).

Average visibility in September
Frederick, CO

Average visibility in September - Frederick, CO
  • Average visibility in September: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

Frederick, Colorado, USA

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