October Weather in Portsmouth, United States

Last updated: June 24, 2025

In October, the average temperature in Portsmouth, United States is a pleasant 19°C (66°F). Expect a range from a cool 4°C (39°F) to a warm 34°C (93°F). With an average humidity of 80%, be prepared for a noteworthy 91 mm (3.6 in) of precipitation over about 9 days.

October Temperature in Portsmouth

In October in Portsmouth, the average temperature is 19°C (66°F), with maximums reaching 34°C (93°F) and minimums dropping as low as 4°C (39°F). It's a wonderful time for travelers to experience comfortable weather while enjoying outdoor activities.

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

The chart illustrates October 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, October typically has an average temperature of 19°C (66°F), with highs reaching up to 34°C (93°F) and lows dropping to around 4°C (39°F).

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

October Precipitation in Portsmouth

In Portsmouth in October, the precipitation amount is 91 mm (3.6 in) spread over 9 days.

October Precipitation Trends in Portsmouth

The chart displays monthly precipitation patterns in Portsmouth, with values for each month alongside October’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how October’s conditions compare to those of other months. In Portsmouth, October typically receives around 91 mm (3.6 inches) of precipitation spread over approximately 9 days.

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

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Millimeters (mm) Inches (in)

October Humidity in Portsmouth

In Portsmouth in October humidity is 80%. With an average temperature of 19°C (66°F), this humidity feels like a warm, thick blanket wrapping around you, making outdoor activities feel more strenuous and sticky, which can ultimately dampen the experience of traveling.

October Average Humidity in Portsmouth

This chart illustrates the average monthly humidity levels in Portsmouth, with October’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In October, average humidity in Portsmouth is approximately 80%, offering insight into how humid the weather typically is during this month.

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

October UV Index in Portsmouth

In Portsmouth in October, 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 Portsmouth.

Maximum UV Index Levels in Portsmouth for October

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

Data source: Portsmouth October 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 October 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 October’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 October’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	6°C (43°F)	90 mm (3.5 inches)	84%	moderate
February Weather	8°C (47°F)	99 mm (3.9 inches)	83%	high
March Weather	10°C (51°F)	79 mm (3.1 inches)	82%	very high
April Weather	16°C (60°F)	97 mm (3.8 inches)	81%	very high
May Weather	20°C (69°F)	121 mm (4.7 inches)	80%	very high
June Weather	24°C (76°F)	121 mm (4.8 inches)	82%	very high
July Weather	27°C (81°F)	142 mm (5.6 inches)	81%	extreme
August Weather	26°C (79°F)	169 mm (6.6 inches)	81%	very high
September Weather	24°C (75°F)	127 mm (5.0 inches)	78%	very high
October Weather	19°C (66°F)	91 mm (3.6 inches)	80%	very high
November Weather	11°C (53°F)	78 mm (3.1 inches)	84%	moderate
December Weather	8°C (47°F)	89 mm (3.5 inches)	84%	moderate