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September Weather in Diamond City, United States

Last updated: June 24, 2025

In September, the average temperature in Diamond City, United States hovers around 23°C (74°F). Expect a minimum of 8°C (47°F) and occasional peaks reaching up to 35°C (96°F). With an average humidity of 64% and precipitation totaling 51 mm (2.0 in) over 6 days, this month offers a mix of comfortable conditions and refreshing showers.

September Temperature in Diamond City

In September in Diamond City, the average temperature is 23°C (74°F). The maximum can reach 35°C (96°F), and the minimum can drop as low as 8°C (47°F). This variety in temperatures makes Diamond City a suitable destination for travelers seeking both warm days and cooler evenings.

September Weather in Diamond City: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Diamond City, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Diamond City, September typically has an average temperature of 23°C (74°F), with highs reaching up to 35°C (96°F) and lows dropping to around 8°C (47°F).
JanFebMarAprMayJunJulAugSepOctNovDec374051576776807874614843
Data source: Temperature data for Diamond City 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 Diamond City

In Diamond City in September, the precipitation amount is 51 mm (2.0 in) over the course of 6 days.

September Precipitation Trends in Diamond City

The chart displays monthly precipitation patterns in Diamond City, 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 Diamond City, September typically receives around 51 mm (2.0 inches) of precipitation spread over approximately 6 days.
JanFebMarAprMayJunJulAugSepOctNovDec80991441591829377125511207278
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Diamond City

In Diamond City in September, humidity is 64%. With an average temperature of 23°C (74°F), this humidity feels like a warm blanket wrapping around you, making outdoor exploration enjoyable yet slightly sticky, so it's best to stay hydrated and take breaks in the shade while traveling.

September Average Humidity in Diamond City

This chart illustrates the average monthly humidity levels in Diamond City, 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 Diamond City 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 Diamond City

In Diamond City 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 Diamond City.

Maximum UV Index Levels in Diamond City for September

The chart shows the monthly maximum UV Index (UVI) for Diamond City 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 Diamond City typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec36810111111109753
Data source: Diamond City 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 Diamond City Compares to Other Months

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

This table compares monthly weather conditions in Diamond City, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather3°C (38°F)80 mm (3.2 inches)81%moderate
February Weather5°C (40°F)99 mm (3.9 inches)78%high
March Weather10°C (51°F)144 mm (5.7 inches)76%very high
April Weather14°C (57°F)159 mm (6.3 inches)78%very high
May Weather20°C (67°F)182 mm (7.2 inches)83%extreme
June Weather24°C (76°F)93 mm (3.7 inches)83%extreme
July Weather27°C (80°F)77 mm (3.0 inches)78%extreme
August Weather25°C (78°F)125 mm (4.9 inches)68%very high
September Weather23°C (74°F)51 mm (2.0 inches)64%very high
October Weather16°C (61°F)119 mm (4.7 inches)70%high
November Weather9°C (48°F)72 mm (2.8 inches)83%moderate
December Weather6°C (43°F)78 mm (3.1 inches)87%moderate

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