West Allis (WI) Monthly Rainfall & Precipitation

This page shows both the average monthly rainfall and the number of rainy days in West Allis, Wisconsin, United States of America. These averages rely on historical data collected over 30 years, from 1990 to 2020. Let's now guide you through the details for a complete overview.

Generally, West Allis receives mid-range precipitation levels, with 977 mm (38 in) annually.

Monthly Precipitation Levels

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

The climate in West Allis shows significant variation throughout the year. Expect 141 mm (5.6 in) of precipitation during the wettest month June, distributed over 12 rainy days.

In contrast, January offers drier and sunnier days, with around 36 mm (1.4 in) of snowfall over 10 snowy days.

June, the wettest month, has a maximum daytime temperature of 25°C (77°F). The city receives 305 hours of sunshine in this period. During the driest month January you can expect a temperature of -1°C (30°F). For more detailed insights into the city's temperatures, visit our West Allis Temperature page.

West Allis's average annual precipitation is 977 mm (38 in). Let's compare this to some popular worldwide tourist destinations:

Athens, Greece, receives an average annual precipitation of 400 mm (16 in), making it one of the drier Mediterranean climates with rainfall mostly in winter.

In Seoul, South Korea, the average annual precipitation is 1237 mm (49 in), with most rain falling during the summer monsoon season.

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

Mumbai, India, experiences a tropical monsoon climate with 1860 mm (73 in) of annual rainfall, with the majority of precipitation happening during the monsoon season from June to September.

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.

• 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 West Allis (WI)'s weather, including sunshine hours, humidity levels, and temperature data, visit our West Allis (WI) Climate page.