Grants Pass (OR) Monthly Rainfall & Precipitation

This page shows both the average monthly rainfall and the number of rainy days in Grants Pass, Oregon, United States of America. 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.

Generally, Grants Pass experiences moderate precipitation patterns, averaging 783 mm (31 in) yearly. However, this average masks significant seasonal variation, including a distinct dry season during certain months that are clearly visible in our monthly breakdown below.

Monthly Precipitation Levels

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

The seasons in Grants Pass, bring significant changes in precipitation. The wettest month, December, receives heavy rainfall, with an average of 166 mm (6.5 in) of precipitation. This rainfall is distributed across 18 rainy days.

December, the wettest month, has a maximum daytime temperature of 8°C (46°F). During the driest month August you can expect a temperature of 32°C (90°F). For more detailed insights into the city's temperatures, visit our Grants Pass Temperature page.

Grants Pass's average annual precipitation is 783 mm (31 in). Let's compare this to some popular worldwide tourist destinations:

Boston, USA, experiences 1238 mm (49 in) of annual precipitation, including significant snowfall during the winter.

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

In Tokyo, Japan, the average annual precipitation is 1528 mm (60 in), with significant summer rains due to typhoon season.

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.

• "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 (15 inches) wide and 20 cm (7.9 inches) 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 (103 feet) fell during the winter of 1972.

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