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September Weather in Summit, United States

Last updated: June 24, 2025

In Summit, United States during September, the average temperature hovers around 26°C (78°F), with a minimum of 11°C (51°F) and a maximum soaring up to 38°C (100°F). Expect about 111 mm (4.4 in) of precipitation across 11 days, resulting in an average humidity level of 79%. It's a month that beautifully balances warmth and moisture!

September Temperature in Summit

In September in Summit, the average temperature is 26°C (78°F). Maximum can reach 38°C (100°F) and minimum can be as low as 11°C (51°F). Travelers should be prepared for warm days and cooler evenings while enjoying the diverse climate.

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 26°C (78°F), with highs reaching up to 38°C (100°F) and lows dropping to around 11°C (51°F).
JanFebMarAprMayJunJulAugSepOctNovDec505662657479818078705753
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 111 mm (4.4 in), occurring over the course of 11 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 111 mm (4.4 inches) of precipitation spread over approximately 11 days.
JanFebMarAprMayJunJulAugSepOctNovDec12512511814517415115017511110790147
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 79%. With an average temperature of 26°C (78°F), this humidity feels like a tropical blanket enveloping you, making outdoor activities less comfortable for traveling.

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 79%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec83%83%80%81%81%78%79%79%79%77%85%88%
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 reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. For more 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 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec589111112121110864
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 Weather10°C (50°F)125 mm (4.9 inches)83%moderate
February Weather13°C (56°F)125 mm (4.9 inches)83%very high
March Weather17°C (62°F)118 mm (4.6 inches)80%very high
April Weather19°C (66°F)144 mm (5.7 inches)81%extreme
May Weather23°C (74°F)173 mm (6.8 inches)81%extreme
June Weather26°C (79°F)151 mm (5.9 inches)78%extreme
July Weather27°C (81°F)150 mm (5.9 inches)79%extreme
August Weather27°C (80°F)175 mm (6.9 inches)79%extreme
September Weather26°C (78°F)111 mm (4.4 inches)79%very high
October Weather21°C (70°F)107 mm (4.2 inches)77%very high
November Weather14°C (57°F)90 mm (3.5 inches)85%high
December Weather12°C (54°F)147 mm (5.8 inches)88%moderate

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