Johnston Monthly Rainfall & Precipitation

This page shows both the average monthly rainfall and the number of rainy days in Johnston, Dyfed, United Kingdom. These values are calculated using 30 years of data (1990–2020) to ensure accuracy. Now, let's explore all the details to give you a full picture.

Johnston is known for its substantial rainfall, with annual precipitation reaching 1098 mm (43 in).

Monthly Precipitation Levels

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

While rainfall varies throughout the year, each season offers its own charm. November brings wetter days averaging 128 mm (5 in) of precipitation, spread over 19 rainy days.

In contrast, May experiences a drier climate, with about 67 mm (2.6 in) of rainfall spread across 14 rainy days.

November, the wettest month, has a maximum daytime temperature of 13°C (55°F). During the driest month May you can expect a temperature of 15°C (59°F). For more detailed insights into the city's temperatures, visit our Johnston Temperature page.

Johnston's average annual precipitation is 1098 mm (43 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.

Osaka, Japan, experiences 1507 mm (59 in) of rainfall annually, spread across the year with wetter summers.

In Brisbane, Australia, the annual precipitation is 979 mm (39 in), making it wetter than Sydney.

Singapore, situated near the equator, gets 2581 mm (102 in) of rainfall annually, with no distinct dry season and consistent monthly precipitation.

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.

• 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 Johnston's weather, including sunshine hours, humidity levels, and temperature data, visit our Johnston Climate page.