Helena (MT) Rainfall & Precipitation: Monthly Averages and Year-Round Insights

This page shows the average amount of rainfall per month in Helena (MT). The numbers are calculated over a 30-year period to provide a reliable average. Now, let’s explore all the details to give you a full picture.

Helena's climate is marked by below-average rain/snowfall, accumulating 373 mm of precipitation yearly.

Monthly Precipitation Levels

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

Helena can be quite wet during May, receiving approximately 59 mm of precipitation over 15 rainy days.

In contrast January, experiences much drier conditions, with 17 mm of snowfall, spread across 11 snowy days.

May, the city’s wettest month, has a maximum daytime temperature of 17°C and receives 282 hours of sunshine. During the driest month January you can expect a temperature of 2°C. For more detailed insights into the city’s temperatures, visit our Helena 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

Helena’s average annual precipitation is 373 mm. Let’s compare this to some popular worldwide tourist destinations:

Chicago, USA, sees an annual precipitation of 1062 mm, with rain and snow contributing to its humid climate.

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

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

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

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