September weather forecast
Lone Tree, CO

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Weather in September

The arrival of September in Lone Tree indicates the commencement of autumn. The weather begins cooling down, and the rainfall frequency decreases noticeably from August. With an average rainfall of just 0.47in, September is the driest month of the year. Transitioning into October, further temperature drops and a slight increase in precipitation establish the fall season fully. Lone Tree dons a colorful facade due to the changing foliage, making it a picturesque destination.

Temperature

The transition into September subtly indicates a reduction in the average high-temperature, down to a still moderately hot 77.7°F (25.4°C) from August's 84.4°F (29.1°C). September's nights in Lone Tree exhibit a sharp contrast from day highs, with an average temperature of 52.5°F (11.4°C).

Humidity

The months with the lowest humidity are June, August and September, with an average relative humidity of 43%.

Rainfall

The month with the least rainfall is September, when the rain falls for 6.5 days and typically collects 0.47" (12mm) of precipitation.

Snowfall

In Lone Tree, snow does not fall in June through September.

Daylight

In September, the average length of the day 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, sunrise is at 6:55 am and sunset at 6:43 pm MDT.

Sunshine

In September, the average sunshine is 11h.

UV index

In Lone Tree, the average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a medium vulnerability from unsafe exposure to UV radiation for the ordinary person.
Note: The daily maximum UV index of 5 in September interprets into the following advice:
Take precautions - Protection against sun damage is advised. Exposing oneself to the midday Sun can be harmful due to the strong UV radiation; limit your time outside. On days when the sun blazes, arm yourself with sunglasses that block UVA and UVB radiation. Keep in mind! Snow's reflective quality can nearly double the intensity of the Sun's UV radiation.
Updated: Jun 17, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are the temperatures in September?

September temperatures vary between a high-temperature of 77.7°F (25.4°C) and a low-temperature of 52.5°F (11.4°C). The average heat index (a.k.a. 'apparent temperature', 'real feel'), which combines relative humidity and air temperature, in August is appraised at 84.2°F (29°C).

What is the least humid month?

June, August and September, with an average relative humidity of 43%, are the least humid months in Lone Tree.

What is the average humidity in September?

In Lone Tree, the average relative humidity in September is 43%.

What is the driest month?

September is the month with the least rainfall. Rain falls for 6.5 days and accumulates 0.47" (12mm) of precipitation.

How much does it rain in Lone Tree in September?

In Lone Tree, during September, the rain falls for 6.5 days and regularly aggregates up to 0.47" (12mm) of precipitation.

When it does not snow?

June through September are months without snowfall.

Does it snow in September?

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

How many hours of daylight does Lone Tree have in September?

In Lone Tree, the average day length in September is 12h and 26min.

What time are sunrise and sunset in September in Lone Tree?

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, sunrise is at 6:55 am and sunset at 6:43 pm MDT.

How many hours of sunshine does Lone Tree have in September?

In September, the average sunshine duration is 11h.

How high is the UV index in September?

The average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a moderate vulnerability from exposure to Sun's UV rays.
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
Lone Tree, CO

Average temperature in September - Lone Tree, CO
  • Average high temperature in September: 77.7°F

The warmest month (with the highest average high temperature) is July (85.6°F).
The month with the lowest average high temperature is December (40.3°F).

  • Average low temperature in September: 52.5°F

The month with the highest average low temperature is July (59.2°F).
The coldest month (with the lowest average low temperature) is December (20.7°F).

Average pressure in September
Lone Tree, CO

Average pressure in September - Lone Tree, CO
  • Average pressure in September: 30.01"Hg

The month with the highest atmospheric pressure is January (30.13"Hg).
The months with the lowest atmospheric pressure are April and June (29.91"Hg).

Average wind speed in September
Lone Tree, CO

Average wind speed in September - Lone Tree, CO
  • Average wind speed in September: 6.6mph

The windiest month (with the highest average wind speed) is April (7.8mph).
The calmest months (with the lowest average wind speed) are August and December (6.5mph).

Average humidity in September
Lone Tree, CO

Average humidity in September - Lone Tree, CO
  • Average humidity in September: 43%

The month with the highest relative humidity is February (65%).
The months with the lowest relative humidity are June, August and September (43%).

Average rainfall in September
Lone Tree, CO

Average rainfall in September - Lone Tree, CO
  • Average rainfall in September: 0.47"

The wettest month (with the highest rainfall) is May (2.2").
The driest month (with the least rainfall) is September (0.47").

Average rainfall days in September
Lone Tree, CO

Average rainfall days in September - Lone Tree, CO
  • Average rainfall days in September: 6.5 days

The month with the highest number of rainy days is May (14.2 days).
The month with the least rainy days is November (3.4 days).

Average snowfall in September
Lone Tree, CO

Average snowfall in September - Lone Tree, CO
  • Average snowfall in September: 0"

The month with the highest snowfall is April (6.34").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in September
Lone Tree, CO

Average snowfall days in September - Lone Tree, CO
  • Average snowfall days in September: 0.1 days

The month with the highest number of snowfall days is February (9.4 days).
The months with the least snowfall days are June, July and August (0 days).

Average daylight in September /
Average sunshine in September
Lone Tree, CO

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

The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 24min).

  • Average sunshine in September: 11h and 0min

The months with the most sunshine are June and July (Average sunshine: 11h and 54min).
The month with the least sunshine is February (Average sunshine: 6h and 48min).

Average sunshine days in September
Lone Tree, CO

Average sunshine days in September - Lone Tree, CO
  • Average sunshine days in September: 21 days

The month with the most sunshine days is November (23.2 days).
The month with the least sunshine days is April (12.7 days).

Average UV index in September
Lone Tree, CO

Average UV index in September - Lone Tree, CO
  • Average UV index in September: 5

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
Lone Tree, CO

Average cloud cover in September - Lone Tree, CO
  • Average cloud cover in September: 15

The month with the most cloud cover is April (Cloud cover 26).
The months with the least cloud cover are June and September (Cloud cover 15).

Average visibility in September
Lone Tree, CO

Average visibility in September - Lone Tree, 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).

Lone Tree, Colorado, USA

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