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September Weather in Summit, United States

Last updated: June 24, 2025

In September, the average temperature in Summit, United States hovers around 23°C (75°F), creating a pleasant atmosphere for outdoor activities. Temperatures can dip to a chilly 9°C (48°F) at night or soar up to a sweltering 35°C (95°F) during the day. Expect a total precipitation of approximately 56 mm (2.2 in) over about 6 rainy days, with an average humidity level of 64%, making for a comfortably humid climate. Enjoy your stay!

September Temperature in Summit

In September in Summit, the average temperature is 23°C (75°F), with maximums reaching 35°C (95°F) and minimums as low as 9°C (48°F). This mild climate makes it a great time for travelers to explore all that Summit has to offer.

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

The chart illustrates September temperature patterns in Summit, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Summit, September typically has an average temperature of 23°C (75°F), with highs reaching up to 35°C (95°F) and lows dropping to around 9°C (48°F).
JanFebMarAprMayJunJulAugSepOctNovDec384152576876807874614844
Data source: Temperature data for Summit 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 Summit

In Summit in September, the precipitation amount is 56 mm (2.2 in) spread over 6 days.

September Precipitation Trends in Summit

The chart displays monthly precipitation patterns in Summit, 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 Summit, September typically receives around 56 mm (2.2 inches) of precipitation spread over approximately 6 days.
JanFebMarAprMayJunJulAugSepOctNovDec751021331401708467110561017181
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Summit

In Summit in September, humidity is 64%. With an average temperature of 23°C (75°F), this humidity feels like a warm, tropical embrace, making travel somewhat sticky but also invigorating, as the air wraps around you, enriching every breath with a hint of that seasonal atmosphere.

September Average Humidity in Summit

This chart illustrates the average monthly humidity levels in Summit, 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 Summit is approximately 64%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec81%78%76%78%83%83%78%68%64%70%83%87%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Summit

In Summit in September, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Summit.

Maximum UV Index Levels in Summit for September

The chart shows the monthly maximum UV Index (UVI) for Summit 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 Summit typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec36710101111109753
Data source: Summit 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 Summit Compares to Other Months

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

This table compares monthly weather conditions in Summit, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather3°C (39°F)75 mm (3.0 inches)81%moderate
February Weather5°C (41°F)101 mm (4.0 inches)78%high
March Weather11°C (52°F)133 mm (5.2 inches)76%high
April Weather14°C (58°F)140 mm (5.5 inches)78%very high
May Weather20°C (68°F)170 mm (6.7 inches)83%very high
June Weather25°C (77°F)84 mm (3.3 inches)83%extreme
July Weather27°C (81°F)67 mm (2.6 inches)78%extreme
August Weather26°C (78°F)110 mm (4.3 inches)68%very high
September Weather23°C (75°F)56 mm (2.2 inches)64%very high
October Weather16°C (62°F)101 mm (4.0 inches)70%high
November Weather9°C (49°F)71 mm (2.8 inches)83%moderate
December Weather7°C (44°F)81 mm (3.2 inches)87%moderate

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