Portsmouth (NH) Rainfall & Precipitation: Monthly Averages and Year-Round Insights

This page shows the average amount of rainfall per month in Portsmouth (NH). The numbers are calculated over a 30-year period to provide a reliable average. Let's now guide you through the details for a complete overview.

Portsmouth has a relatively rain/snowy climate with high precipitation levels, averaging 1315 mm of rain/snowfall annually.

Monthly Precipitation Levels

The average number of days each month with precipitation (> 0.2 mm)

Precipitation levels in Portsmouth remain relatively steady throughout the year. June has the most rain, with 139 mm over 14 days. In January, this drops slightly to 86 mm, making the city's climate fairly predictable.

June, the city’s wettest month, has a maximum daytime temperature of 23°C and receives 274 hours of sunshine. During the driest month January you can expect a temperature of 1°C. For more detailed insights into the city’s temperatures, visit our Portsmouth Temperature page.

Annual Precipitation in the United States of America

The map below shows the annual precipitation across the United States of America. You can also select the different months in case you are interested in a specific month.

Amsterdam Precipitation Compared World Wide

Portsmouth’s average annual precipitation is 1315 mm. Let’s compare this to some popular worldwide tourist destinations:

In Barcelona, Spain, the average annual precipitation is 644 mm, evenly distributed across the year with no extreme wet or dry seasons.

Meanwhile, Buenos Aires, Argentina, enjoys a humid subtropical climate with 1000 mm of annual rainfall, mostly in the summer.

In Tokyo, Japan, the average annual precipitation is 1528 mm, with significant summer rains due to typhoon season.

Kuala Lumpur, Malaysia, receives 2529 mm of annual rainfall, characteristic of its equatorial tropical rainforest climate, with consistent rainfall throughout the year and peak months during March and November.

How is Precipitation Measured?

Precipitation amounts are measured using specific gauges installed at weather stations, collecting both rain and snow and any other type of precipitation. Rainfall is measured directly in millimeters, while that from snow and ice is obtained by melting it. Automated systems often incorporate heaters to make this easier.

Information from these stations is transmitted via Wi-Fi, satellite, GPS, or telephone connections to central monitoring networks. This information is immediately updated and integrated into weather models and forecasts.

Interesting weather facts

• The U.S. has a significant number of thunderstorms every year, with over 14.6 million taking place across the world annually.
• Approximately 70% of lightning bolts strike land rather than oceans.
• A storm named John was the longest-lasting Pacific tropical storm, continuing for 31 days. As it crossed the dateline twice, it changed status from a hurricane to a typhoon and back to a hurricane.

For more detailed information about Portsmouth (NH)’s weather, including sunshine hours, humidity levels, and temperature data, visit our Portsmouth (NH) Climate page.