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August Weather in Cornwall, Canada

Last updated: June 18, 2025

In August, the average temperature in Cornwall, Canada hovers around 21°C (70°F), making it a pleasant time to visit. Expect a minimum temperature of 8°C (47°F) and a maximum reaching up to 33°C (91°F). While you enjoy the mild weather, be prepared for around 100 mm (3.9 in) of precipitation spread over 14 days, resulting in an average humidity level of 75%.

August Temperature in Cornwall

In August in Cornwall, the average temperature is 21°C (70°F), with maximums reaching up to 33°C (91°F) and minimums dipping as low as 8°C (47°F). This makes it an ideal time for travelers to enjoy a mix of warm days and cooler evenings, perfect for outdoor activities and sightseeing.

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

The chart illustrates August temperature patterns in Cornwall, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Cornwall, August typically has an average temperature of 21°C (70°F), with highs reaching up to 33°C (91°F) and lows dropping to around 8°C (47°F).
JanFebMarAprMayJunJulAugSepOctNovDec192230435766716962503626
Data source: Temperature data for Cornwall 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 Cornwall

In Cornwall in August, the total precipitation amount is 100 mm (3.9 in) spread over 14 days.

August Precipitation Trends in Cornwall

The chart displays monthly precipitation patterns in Cornwall, 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 Cornwall, August typically receives around 100 mm (3.9 inches) of precipitation spread over approximately 14 days.
JanFebMarAprMayJunJulAugSepOctNovDec8583871171091001161007013910884
Data source: Precipitation data for August generated using information from the Copernicus Climate Change Service.
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August Humidity in Cornwall

In Cornwall in August, humidity is 75%. With an average temperature of 21°C (70°F), this humidity feels like a warm, enveloping blanket that makes exploring the area feel slightly sticky, requiring travelers to stay hydrated and take occasional breaks in the shade to fully enjoy their adventures.

August Average Humidity in Cornwall

This chart illustrates the average monthly humidity levels in Cornwall, 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 Cornwall is approximately 75%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec93%92%86%85%80%74%76%75%78%86%89%89%
Data source: Humidity data for August generated using information from the Copernicus Climate Change Service.

August UV Index in Cornwall

In Cornwall in August, 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 Cornwall.

Maximum UV Index Levels in Cornwall for August

The chart shows the monthly maximum UV Index (UVI) for Cornwall 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 Cornwall typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec245899987532
Data source: Cornwall 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 Cornwall Compares to Other Months

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

This table compares monthly weather conditions in Cornwall, showing how August’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-7°C (20°F)85 mm (3.3 inches)93%low
February Weather-6°C (22°F)83 mm (3.3 inches)92%moderate
March Weather-1°C (30°F)87 mm (3.4 inches)86%moderate
April Weather6°C (44°F)117 mm (4.6 inches)85%very high
May Weather14°C (57°F)109 mm (4.3 inches)80%very high
June Weather19°C (66°F)100 mm (3.9 inches)74%very high
July Weather22°C (72°F)116 mm (4.6 inches)76%very high
August Weather21°C (70°F)100 mm (3.9 inches)75%very high
September Weather16°C (62°F)70 mm (2.8 inches)78%high
October Weather10°C (51°F)139 mm (5.5 inches)86%moderate
November Weather2°C (36°F)108 mm (4.2 inches)88%moderate
December Weather-3°C (26°F)84 mm (3.3 inches)89%low

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