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August Weather in Boston, United States

Last updated: June 24, 2025

In Boston, United States, the average temperature in August reaches a warm 27°C (82°F), with daily highs soaring up to 37°C (99°F) and dipping to a comfortable 19°C (66°F). Expect 137 mm (5.4 in) of precipitation spread over 21 days, and humidity levels hover around a sticky 79%. Embrace the warmth and prepare for those occasional showers!

August Temperature in Boston

In August in Boston, the average temperature is 27°C (82°F). The maximum can reach 37°C (99°F), and the minimum can be as low as 19°C (66°F). This makes it an ideal time for travelers seeking warm weather and outdoor activities.

August Weather in Boston: Daily Temperature Highs, Lows, and Averages

The chart illustrates August temperature patterns in Boston, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Boston, August typically has an average temperature of 27°C (82°F), with highs reaching up to 37°C (99°F) and lows dropping to around 19°C (66°F).
JanFebMarAprMayJunJulAugSepOctNovDec535963687680818180736056
Data source: Temperature data for Boston 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.

August Precipitation in Boston

In Boston in August, the precipitation amount is 137 mm (5.4 in) over the course of 21 days.

August Precipitation Trends in Boston

The chart displays monthly precipitation patterns in Boston, with values for each month alongside August’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how August’s conditions compare to those of other months. In Boston, August typically receives around 137 mm (5.4 inches) of precipitation spread over approximately 21 days.
JanFebMarAprMayJunJulAugSepOctNovDec72965280741571481371107350118
Data source: Precipitation data for August generated using information from the Copernicus Climate Change Service.
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August Humidity in Boston

In Boston in August humidity is 79%. With an average temperature of 27°C (82°F), this humidity feels like traveling through a warm, thick blanket, making every step feel heavier and more exhausting, while the air clings to your skin, reminding you to stay hydrated and take frequent breaks in the shade.

August Average Humidity in Boston

This chart illustrates the average monthly humidity levels in Boston, with August’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In August, average humidity in Boston is approximately 79%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec85%82%80%76%73%74%80%79%83%77%84%88%
Data source: Humidity data for August generated using information from the Copernicus Climate Change Service.

August UV Index in Boston

In Boston in August, the maximum UV index reaches 11, which corresponds to an extreme Exposure Category. With a time to burn of just 10 minutes, it's essential to take precautions. For more details, you can check the Hourly UV Index in Boston.

Maximum UV Index Levels in Boston for August

The chart shows the monthly maximum UV Index (UVI) for Boston in August, 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 August, the maximum UV index in Boston typically reaches 11, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec589101111111110864
Data source: Boston August 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 August Weather in Boston Compares to Other Months

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

This table compares monthly weather conditions in Boston, showing how August’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather12°C (54°F)72 mm (2.8 inches)85%moderate
February Weather15°C (60°F)96 mm (3.8 inches)82%very high
March Weather17°C (64°F)52 mm (2.1 inches)80%very high
April Weather20°C (69°F)80 mm (3.1 inches)76%very high
May Weather25°C (76°F)74 mm (2.9 inches)73%extreme
June Weather27°C (80°F)157 mm (6.2 inches)74%extreme
July Weather27°C (81°F)148 mm (5.8 inches)80%extreme
August Weather27°C (82°F)137 mm (5.4 inches)79%extreme
September Weather26°C (80°F)110 mm (4.3 inches)83%very high
October Weather23°C (74°F)73 mm (2.9 inches)77%very high
November Weather16°C (61°F)50 mm (2.0 inches)84%high
December Weather13°C (56°F)117 mm (4.6 inches)88%moderate

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