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August Weather in Portsmouth, United States

Last updated: June 24, 2025

In August, the average temperature in Portsmouth, United States is a pleasant 22°C (73°F). Expect a comfortable range with minimum temperatures dipping to 16°C (61°F) and maximum highs reaching 28°C (83°F). You might want to prepare for some rain, as the area sees about 89 mm (3.5 in) of precipitation over approximately 10 days. With an average humidity of 76%, it’s the perfect time to explore the charming atmosphere of your destination!

August Temperature in Portsmouth

In August in Portsmouth, the average temperature is 22°C (73°F), with maximums reaching 28°C (83°F) and minimums dropping as low as 16°C (61°F). This pleasant weather makes it an ideal time for traveling and outdoor adventures.

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

The chart illustrates August temperature patterns in Portsmouth, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Portsmouth, August typically has an average temperature of 22°C (73°F), with highs reaching up to 28°C (83°F) and lows dropping to around 16°C (61°F).
JanFebMarAprMayJunJulAugSepOctNovDec353638465464727267594839
Data source: Temperature data for Portsmouth 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 Portsmouth

In Portsmouth in August, the precipitation amount is 89 mm (3.5 in) over a period of 10 days.

August Precipitation Trends in Portsmouth

The chart displays monthly precipitation patterns in Portsmouth, 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 Portsmouth, August typically receives around 89 mm (3.5 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec9612111914713310410489110169117147
Data source: Precipitation data for August generated using information from the Copernicus Climate Change Service.
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August Humidity in Portsmouth

In Portsmouth in August, humidity is 76%. With an average temperature of 22°C (73°F), this humidity feels like a warm embrace that envelops you, making travel both refreshing and slightly steamy, as the air clings warmly to your skin.

August Average Humidity in Portsmouth

This chart illustrates the average monthly humidity levels in Portsmouth, 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 Portsmouth is approximately 76%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%84%82%79%75%78%76%76%76%75%80%80%
Data source: Humidity data for August generated using information from the Copernicus Climate Change Service.

August UV Index in Portsmouth

In Portsmouth in August, 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 Portsmouth.

Maximum UV Index Levels in Portsmouth for August

The chart shows the monthly maximum UV Index (UVI) for Portsmouth 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 Portsmouth typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3568910998642
Data source: Portsmouth 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 Portsmouth Compares to Other Months

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

This table compares monthly weather conditions in Portsmouth, showing how August’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather1°C (35°F)95 mm (3.8 inches)84%moderate
February Weather2°C (36°F)121 mm (4.8 inches)84%moderate
March Weather3°C (39°F)119 mm (4.7 inches)82%high
April Weather8°C (46°F)147 mm (5.8 inches)79%very high
May Weather12°C (55°F)132 mm (5.2 inches)75%very high
June Weather18°C (64°F)104 mm (4.1 inches)78%very high
July Weather22°C (72°F)104 mm (4.1 inches)76%very high
August Weather22°C (73°F)89 mm (3.5 inches)76%very high
September Weather20°C (67°F)110 mm (4.3 inches)75%very high
October Weather15°C (60°F)169 mm (6.7 inches)75%high
November Weather9°C (48°F)117 mm (4.6 inches)80%moderate
December Weather4°C (39°F)147 mm (5.8 inches)80%low

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