Saint Helens (OR) Rainfall & Precipitation: Monthly Averages and Year-Round Insights

This page shows the average amount of rainfall per month in Saint Helens (OR). 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.

Saint Helens experiences significant rain/snowfall throughout the year, averaging 1096 mm of precipitation annually.

Monthly Precipitation Levels

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

The seasons in Saint Helens, bring significant changes in precipitation. The wettest month, December, receives heavy rainfall, with an average of 198 mm of precipitation.

This rainfall is distributed across 22 rainy days. In contrast, the driest month, July, experiences much less rainfall, totaling 12 mm over 4 rainy days. These distinct seasonal differences provide diverse experiences throughout the year.

December, the city’s wettest month, has a maximum daytime temperature of 7°C. During the driest month July you can expect a temperature of 27°C. For more detailed insights into the city’s temperatures, visit our Saint Helens 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

Saint Helens’s average annual precipitation is 1096 mm. Let’s compare this to some popular worldwide tourist destinations:

Boston, USA, experiences 1238 mm of annual precipitation, including significant snowfall during the winter.

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

Adelaide, Australia, enjoys 511 mm of annual precipitation, with dry summers and wet winters.

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

• "Ginger" was the longest-lasting Atlantic tropical storm, which spun around the open ocean for 28 days in 1971.
• The world's largest snowflake was recorded in the Guinness Book of Records, at 38 cm wide and 20 cm thick. The snowflake fell at Fort Keogh, Montana, USA, on 28 January 1887.
• The greatest snowfall recorded was on Mt. Rainier, Washington State, USA—over 31.5 meters fell during the winter of 1972.

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