March Weather in Portsmouth, United States

Last updated: June 24, 2025

In March, the average temperature in Portsmouth, United States is a chilly 3°C (39°F). You can expect a wide range of temperatures, with a minimum dipping to -9°C (16°F) and a maximum reaching 15°C (58°F). Be prepared for 119 mm (4.7 in) of precipitation over 10 days, and keep in mind that the average humidity hovers around 82%.

March Temperature in Portsmouth

In March in Portsmouth, the average temperature is 3°C (39°F). Maximums can reach 15°C (58°F) and minimums can be as low as -9°C (16°F). It's advisable to pack layers and prepare for varying weather conditions during your travels.

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

The chart illustrates March 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, March typically has an average temperature of 3°C (39°F), with highs reaching up to 15°C (58°F) and lows dropping to around -9°C (16°F).

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

March Precipitation in Portsmouth

In Portsmouth in March, the total precipitation amount is 119 mm (4.7 in) over the span of 10 days.

March Precipitation Trends in Portsmouth

The chart displays monthly precipitation patterns in Portsmouth, with values for each month alongside March’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how March’s conditions compare to those of other months. In Portsmouth, March typically receives around 119 mm (4.7 inches) of precipitation spread over approximately 10 days.

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

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Millimeters (mm) Inches (in)

March Humidity in Portsmouth

In Portsmouth in March humidity is 82%. With an average temperature of 3°C (39°F), this humidity feels like a chilling dampness that seeps into your bones, making outdoor exploration uncomfortable and challenging for travel.

March Average Humidity in Portsmouth

This chart illustrates the average monthly humidity levels in Portsmouth, with March’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In March, average humidity in Portsmouth is approximately 82%, offering insight into how humid the weather typically is during this month.

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

March UV Index in Portsmouth

In Portsmouth in March, the maximum UV index is 6, which corresponds to a high Exposure Category. The time to burn is approximately 25 minutes. To find the hourly UV index in Portsmouth, you can refer to this Hourly UV Index in Portsmouth.

Maximum UV Index Levels in Portsmouth for March

The chart shows the monthly maximum UV Index (UVI) for Portsmouth in March, 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 March, the maximum UV index in Portsmouth typically reaches 6, which falls under the high exposure category.

Data source: Portsmouth March 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 March 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 March’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 March’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	1°C (35°F)	95 mm (3.8 inches)	84%	moderate
February Weather	2°C (36°F)	121 mm (4.8 inches)	84%	moderate
March Weather	3°C (39°F)	119 mm (4.7 inches)	82%	high
April Weather	8°C (46°F)	147 mm (5.8 inches)	79%	very high
May Weather	12°C (55°F)	132 mm (5.2 inches)	75%	very high
June Weather	18°C (64°F)	104 mm (4.1 inches)	78%	very high
July Weather	22°C (72°F)	104 mm (4.1 inches)	76%	very high
August Weather	22°C (73°F)	89 mm (3.5 inches)	76%	very high
September Weather	20°C (67°F)	110 mm (4.3 inches)	75%	very high
October Weather	15°C (60°F)	169 mm (6.7 inches)	75%	high
November Weather	9°C (48°F)	117 mm (4.6 inches)	80%	moderate
December Weather	4°C (39°F)	147 mm (5.8 inches)	80%	low