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September Weather in Littleton, United States

Last updated: June 24, 2025

In September, the average temperature in Littleton, United States hovers around 15°C (58°F), offering a mild climate for visitors. However, temperatures can vary significantly, with minimums plunging to -5°C (23°F) and soaring to a maximum of 29°C (85°F). Expect 69 mm (2.7 in) of precipitation over about 9 days, contributing to an average humidity level of 77%. Plan accordingly for a comfortable stay!

September Temperature in Littleton

In September in Littleton, the average temperature is 15°C (58°F), with maximums reaching 29°C (85°F) and minimums dropping as low as -5°C (23°F). This wide temperature range makes it essential for travelers to pack both light clothing for warm days and warm layers for cooler evenings.

September Weather in Littleton: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Littleton, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Littleton, September typically has an average temperature of 15°C (58°F), with highs reaching up to 29°C (85°F) and lows dropping to around -5°C (23°F).
JanFebMarAprMayJunJulAugSepOctNovDec172027405362676558473222
Data source: Temperature data for Littleton generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Littleton

In Littleton in September, the precipitation amount is 69 mm (2.7 in) spread over 9 days.

September Precipitation Trends in Littleton

The chart displays monthly precipitation patterns in Littleton, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In Littleton, September typically receives around 69 mm (2.7 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec8685771251041091199169140116100
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Littleton

In Littleton in September, humidity is 77%. With an average temperature of 15°C (58°F), this humidity feels like a warm blanket enveloping you, making travel a mix of refreshing breezes and occasional stickiness, which can be quite refreshing while exploring the sights.

September Average Humidity in Littleton

This chart illustrates the average monthly humidity levels in Littleton, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Littleton is approximately 77%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec91%89%85%84%78%72%75%74%77%85%86%85%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Littleton

In Littleton in September, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in Littleton.

Maximum UV Index Levels in Littleton for September

The chart shows the monthly maximum UV Index (UVI) for Littleton in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In September, the maximum UV index in Littleton typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec2468910997532
Data source: Littleton September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

How September Weather in Littleton Compares to Other Months

Weather in Littleton varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Littleton, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Littleton, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-8°C (17°F)86 mm (3.4 inches)91%low
February Weather-7°C (20°F)85 mm (3.4 inches)89%moderate
March Weather-3°C (27°F)77 mm (3.0 inches)85%high
April Weather4°C (40°F)125 mm (4.9 inches)84%very high
May Weather12°C (53°F)104 mm (4.1 inches)78%very high
June Weather17°C (62°F)109 mm (4.3 inches)72%very high
July Weather19°C (67°F)119 mm (4.7 inches)75%very high
August Weather18°C (66°F)91 mm (3.6 inches)74%very high
September Weather15°C (58°F)69 mm (2.7 inches)77%high
October Weather8°C (47°F)140 mm (5.5 inches)85%moderate
November Weather0°C (32°F)116 mm (4.6 inches)86%moderate
December Weather-6°C (22°F)100 mm (3.9 inches)85%low

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