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September Weather in Baltimore, United States

Last updated: June 24, 2025

In September, the average temperature in Baltimore, United States is a pleasant 20°C (69°F), with the mercury dipping as low as 4°C (40°F) and soaring to a sizzling 35°C (96°F). Expect 96 mm (3.8 in) of precipitation spread over 8 days, contributing to an average humidity of 73%. This balance of heat and moisture creates a unique climate perfect for exploration!

September Temperature in Baltimore

In September in Baltimore, the average temperature is 20°C (69°F). Maximum temperatures can reach 35°C (96°F), while minimum temperatures can drop as low as 4°C (40°F). Be prepared for a range of weather conditions when traveling during this month in Baltimore.

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

The chart illustrates September temperature patterns in Baltimore, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Baltimore, September typically has an average temperature of 20°C (69°F), with highs reaching up to 35°C (96°F) and lows dropping to around 4°C (40°F).
JanFebMarAprMayJunJulAugSepOctNovDec323543526472767369584237
Data source: Temperature data for Baltimore 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 Baltimore

In Baltimore in September, the precipitation amount is 96 mm (3.8 in) over the course of 8 days.

September Precipitation Trends in Baltimore

The chart displays monthly precipitation patterns in Baltimore, 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 Baltimore, September typically receives around 96 mm (3.8 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec911231221341351591289696108103111
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Baltimore

In Baltimore in September humidity is 73%. With an average temperature of 20°C (69°F), this humidity feels like a warm embrace, making travel slightly sticky but ultimately comfortable as long as you stay hydrated and take breaks in the shade.

September Average Humidity in Baltimore

This chart illustrates the average monthly humidity levels in Baltimore, 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 Baltimore is approximately 73%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec88%88%87%85%81%82%81%73%73%78%89%87%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Baltimore

In Baltimore in September, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to the Hourly UV Index in Baltimore.

Maximum UV Index Levels in Baltimore for September

The chart shows the monthly maximum UV Index (UVI) for Baltimore 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 Baltimore typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec356910101098643
Data source: Baltimore 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 Baltimore Compares to Other Months

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

This table compares monthly weather conditions in Baltimore, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather0°C (32°F)90 mm (3.6 inches)88%moderate
February Weather2°C (36°F)123 mm (4.8 inches)88%moderate
March Weather6°C (43°F)122 mm (4.8 inches)87%high
April Weather11°C (53°F)134 mm (5.3 inches)85%very high
May Weather18°C (64°F)135 mm (5.3 inches)81%very high
June Weather22°C (72°F)159 mm (6.3 inches)82%very high
July Weather24°C (76°F)128 mm (5.0 inches)81%very high
August Weather23°C (74°F)96 mm (3.8 inches)73%very high
September Weather20°C (69°F)96 mm (3.8 inches)73%very high
October Weather14°C (58°F)108 mm (4.3 inches)78%high
November Weather6°C (43°F)103 mm (4.1 inches)89%moderate
December Weather3°C (37°F)111 mm (4.4 inches)87%moderate

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