Groton (CT) Rainfall & Precipitation: Monthly Averages and Year-Round Insights

This page shows the average amount of rainfall per month in Groton (CT). 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.

Groton has a relatively rain/snowy climate with high precipitation levels, averaging 1244 mm of rain/snowfall annually.

Monthly Precipitation Levels

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

Precipitation levels in Groton remain relatively steady throughout the year. December has the most rain, with 128 mm over 12 days. In November, this drops slightly to 93 mm, making the city's climate fairly predictable.

December, the city’s wettest month, has a maximum daytime temperature of 7°C and receives 139 hours of sunshine. During the driest month November you can expect a temperature of 12°C. For more detailed insights into the city’s temperatures, visit our Groton 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

Groton’s average annual precipitation is 1244 mm. Let’s compare this to some popular worldwide tourist destinations:

The climate in San Francisco, USA, is influenced by coastal weather, with 469 mm of rainfall mostly during the winter months.

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

In Brisbane, Australia, the annual precipitation is 979 mm, making it wetter than Sydney.

Ho Chi Minh City, Vietnam, receives 1955 mm of annual rainfall, with a pronounced wet season from May to November, typical of its tropical monsoon climate.

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 Groton (CT)’s weather, including sunshine hours, humidity levels, and temperature data, visit our Groton (CT) Climate page.