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August Weather in Saint John, United States

Last updated: June 24, 2025

In Saint John, United States, the average temperature in August is a pleasant 25°C (78°F). However, be prepared for a temperature range where it can dip to 13°C (55°F) and soar up to 39°C (103°F). The month sees an average precipitation of 74 mm (2.9 in), typically spread over 8 days. With an average humidity of 76%, you can expect a warm and somewhat muggy atmosphere.

August Temperature in Saint John

In August in Saint John, the average temperature is 25°C (78°F). Maximums can reach 39°C (103°F), while minimums can drop as low as 13°C (55°F). It's advisable for travelers to prepare for a wide range of temperatures and pack accordingly.

August Weather in Saint John: Daily Temperature Highs, Lows, and Averages

The chart illustrates August temperature patterns in Saint John, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Saint John, August typically has an average temperature of 25°C (78°F), with highs reaching up to 39°C (103°F) and lows dropping to around 13°C (55°F).
JanFebMarAprMayJunJulAugSepOctNovDec323346546577817873564537
Data source: Temperature data for Saint John 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 Saint John

In Saint John in August, the precipitation amount is 74 mm (2.9 in) over a period of 8 days.

August Precipitation Trends in Saint John

The chart displays monthly precipitation patterns in Saint John, 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 Saint John, August typically receives around 74 mm (2.9 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec2621685016862587462812432
Data source: Precipitation data for August generated using information from the Copernicus Climate Change Service.
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August Humidity in Saint John

In Saint John in August humidity is 76%. With an average temperature of 25°C (78°F), this humidity feels like a thick blanket wrapping around you, making every step feel heavier and the air thick, causing travelers to seek shade and refreshment more often.

August Average Humidity in Saint John

This chart illustrates the average monthly humidity levels in Saint John, 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 Saint John is approximately 76%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec75%76%67%70%82%82%81%76%67%72%80%83%
Data source: Humidity data for August generated using information from the Copernicus Climate Change Service.

August UV Index in Saint John

In Saint John in August, 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 Saint John.

Maximum UV Index Levels in Saint John for August

The chart shows the monthly maximum UV Index (UVI) for Saint John 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 Saint John typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec4579101111109753
Data source: Saint John 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 Saint John Compares to Other Months

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

This table compares monthly weather conditions in Saint John, showing how August’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather0°C (33°F)25 mm (1.0 inches)75%moderate
February Weather1°C (34°F)21 mm (0.8 inches)76%moderate
March Weather8°C (47°F)68 mm (2.7 inches)67%high
April Weather12°C (54°F)50 mm (2.0 inches)70%very high
May Weather18°C (65°F)168 mm (6.6 inches)82%very high
June Weather25°C (77°F)62 mm (2.4 inches)82%extreme
July Weather27°C (81°F)58 mm (2.3 inches)81%extreme
August Weather25°C (78°F)74 mm (2.9 inches)76%very high
September Weather23°C (73°F)62 mm (2.4 inches)67%very high
October Weather14°C (57°F)81 mm (3.2 inches)72%high
November Weather7°C (45°F)24 mm (0.9 inches)80%moderate
December Weather3°C (37°F)32 mm (1.3 inches)83%moderate

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