What is the average annual precipitation in Minnesota?
- The average annual precipitation (rainfall plus the water equivalent found in snowfall) in Minnesota ranges from nearly 18 inches in the far northwest to more than 32 inches in the southeast. Precipitation patterns in Minnesota (and across most of the eastern United States) are dictated by proximity to the Gulf of Mexico. Locations closer to the source of warm, moist air provided by the Gulf, receive more precipitation on average. See the normal precipitation maps for Minnesota.
- Approximately two thirds of average annual precipitation falls during the warm months of May through September. However, most of this precipitation is returned to the atmosphere through evaporation from land and water surfaces and through transpiration from plants. The net effect of the balance between "deposits" and "withdrawals" during the growing season is that many of Minnesota's hydrologic systems reach their seasonal lows by the end of September.
- It should be noted that average or "normal" is a mathematical midpoint about which Minnesota's climate varies widely. Located near the center of the North American continent, Minnesota finds itself at a climate "crossroads," influenced by a wide variety of air masses. For this reason, drought and flood are as much a part of the state's climate as "normal" weather.
What is the average annual snowfall in Minnesota?
- The average annual snowfall in Minnesota varies from 36 inches in the southwest to more than 70 inches along the Lake Superior "snow belt." Although snow is an important component of Minnesota's hydrology, the water found in the snow comprises less than 20 percent of the total precipitation received annually.
- Snowfall patterns are driven by the combined influence of moisture supply and temperature. For example, the average annual snowfall for Winona and Roseau (at opposite ends of the state) is approximately the same. Winona, the wetter location, will occasionally receive winter precipitation in the form of rain, whereas the colder and drier Roseau seldom receives winter rain.
- By far the snowiest areas in Minnesota are the Lake Superior highlands, a ridge of higher terrain along Minnesota's "north shore." In addition to receiving snow from the large-scale weather systems moving through the Midwest, the Lake Superior highlands experience localized snow events as well. These localized events are caused by moisture-laden breezes moving onshore from the lake and up the slope, creating and depositing snow.
Where can I obtain Minnesota climate data?
Minnesota climate data can be obtained from the DNR Waters State Climatology Office. This office manages and disseminates historical climate data in order to address questions involving the impact of climate on Minnesota and its citizens. The State Climatology Office can be reached by telephone at 651-296-4214, via e-mail at [email protected], or through the Climatology Working Group website.