Portsmouth Monthly Rainfall & Precipitation

This page shows both the average monthly rainfall and the number of rainy days in Portsmouth, Hampshire, United Kingdom. Long-term data from 1990 to 2020 was used to calculate these averages. Now, let's explore all the details to give you a full picture.

On average, Portsmouth receives a reasonable amount of rainfall, with an annual precipitation of 844 mm (33 in).

Monthly Precipitation Levels

The average number of days each month with precipitation (> 0.2 mm (0.01 in))

Portsmouth offers a pleasant mix of wetter and slightly drier months. The difference in precipitation between November (94 mm (3.7 in)) and March (54 mm (2.1 in)) is not too significant, making the climate enjoyable for visitors and residents alike.

November, the wettest month, has a maximum daytime temperature of 13°C (55°F). The city receives 77 hours of sunshine in this period. During the driest month March you can expect a temperature of 11°C (52°F). For more detailed insights into the city's temperatures, visit our Portsmouth Temperature page.

Portsmouth's average annual precipitation is 844 mm (33 in). Let's compare this to some popular worldwide tourist destinations:

New York City, USA, receives 1276 mm (50 in) of rainfall annually, with precipitation evenly distributed throughout the year.

In Shanghai, China, the annual average precipitation is 1347 mm (53 in), with a humid subtropical climate.

Melbourne, Australia, has 690 mm (27 in) of rainfall annually, spread fairly evenly throughout the year.

Kuala Lumpur, Malaysia, receives 2529 mm (100 in) of annual rainfall, characteristic of its equatorial tropical rainforest climate, with consistent rainfall throughout the year and peak months during March and November.

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.

Precipitation has a very strong role in determining the local climate and ecosystem:

• Changing Rainfall Patterns: Global warming causes drastic changes in the patterns of rainfall. Some areas have been experiencing increased frequency and intensity of rainfall, while other areas experience longer dry spells or even droughts.
• Local Impacts: Many regions are experiencing heavier rainfall in the winter months and drier, hotter summers. This affects agriculture, water resources, and ecosystems.

• Mawsynram in India is noted as being the wettest place on earth, with over 11 meters (36 feet) of rain falling every year.
• In contrast, Antofagasta in Chile is among the driest places on the planet, getting less than 0.1mm (0.004 inches) per year, with some years recording virtually no rainfall.
• Nearly 1,650 thunderstorm cells are estimated over the planet at any given time.

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