August Weather in Castine, United States

Last updated: June 24, 2025

In August, the average temperature in Castine, United States hovers around 20°C (68°F), offering a comfortable climate for outdoor activities. Expect a minimum of 11°C (51°F) and a maximum of 31°C (88°F), providing a pleasant range for all preferences. However, be prepared for 71 mm (2.8 in) of precipitation spread over 9 days, accompanied by an average humidity of 74%.

August Temperature in Castine

In August in Castine, the average temperature is 20°C (68°F). The maximum can reach 31°C (88°F), and the minimum can be as low as 11°C (51°F). This pleasant weather makes Castine an ideal destination for travelers seeking a comfortable climate.

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

The chart illustrates August temperature patterns in Castine, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Castine, August typically has an average temperature of 20°C (68°F), with highs reaching up to 31°C (88°F) and lows dropping to around 11°C (51°F).

Data source: Temperature data for Castine generated using information from the Copernicus Climate Change Service.

August Precipitation in Castine

In Castine in August, the precipitation amount is 71 mm (2.8 in) spread over 9 days.

August Precipitation Trends in Castine

The chart displays monthly precipitation patterns in Castine, 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 Castine, August typically receives around 71 mm (2.8 inches) of precipitation spread over approximately 9 days.

Data source: Precipitation data for August generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

August Humidity in Castine

In Castine in August humidity is 74%. With an average temperature of 20°C (68°F), this humidity feels like a warm, sticky embrace that can make outdoor activities feel exhausting, prompting travelers to seek shade and hydration more often.

August Average Humidity in Castine

This chart illustrates the average monthly humidity levels in Castine, 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 Castine is approximately 74%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for August generated using information from the Copernicus Climate Change Service.

August UV Index in Castine

In Castine 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 Castine.

Maximum UV Index Levels in Castine for August

The chart shows the monthly maximum UV Index (UVI) for Castine 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 Castine typically reaches 8, which falls under the very high exposure category.

Data source: Castine 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 Castine Compares to Other Months

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

This table compares monthly weather conditions in Castine, showing how August’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-4°C (25°F)	93 mm (3.7 inches)	88%	low
February Weather	-3°C (26°F)	88 mm (3.5 inches)	88%	moderate
March Weather	0°C (32°F)	71 mm (2.8 inches)	85%	moderate
April Weather	6°C (43°F)	130 mm (5.1 inches)	81%	high
May Weather	11°C (52°F)	89 mm (3.5 inches)	76%	very high
June Weather	16°C (62°F)	75 mm (3.0 inches)	74%	very high
July Weather	19°C (67°F)	86 mm (3.4 inches)	74%	very high
August Weather	20°C (68°F)	71 mm (2.8 inches)	74%	very high
September Weather	16°C (61°F)	83 mm (3.3 inches)	77%	high
October Weather	11°C (52°F)	121 mm (4.8 inches)	82%	moderate
November Weather	4°C (39°F)	122 mm (4.8 inches)	85%	moderate
December Weather	-2°C (29°F)	133 mm (5.2 inches)	84%	low