Spring storms that emerged with the receding of winter brought heavy rains across much of the United States. Now, Americans are looking forward to summer — which in some regions is a dry season. No matter where you are in the country, however, there is always the chance of rain.
The United States is home to wildly diverse climates and weather patterns. 24/7 Wall St. examined this geographical variation with a focus on precipitation. For each state, we reviewed yearly average rainfall between 1901 and 2000, as well as 30 year average precipitation levels through 2010 from the government scientific agency National Oceanic and Atmospheric Administration (NOAA).
Some states have distinct wet and dry seasons. In an email to 24/7 Wall St., U.S. Department of Agriculture meteorologist Brad Rippey explained that in California, for example, “The wet season, lasting from late autumn to early spring, is driven by storms associated with the polar jet stream, sometimes supplemented by subtropical moisture (atmospheric rivers or ‘pineapple express’).”
California and several southwestern states, during this part of the year have a Mediterranean climate, characterized by sometimes exceedingly dry summers, Rippey said. Elsewhere, such as on the Plains, where moisture from the Gulf of Mexico is pulled into the region, or in near-tropical states like Florida, precipitation peaks during the warm season.
Peak precipitation occurs at different months in different states. In 34 states, the rainiest months are the summer months of May, June, and July. March is the rainiest month in the New England states of Massachusetts, New Jersey, and Rhode Island, as well as in Alabama — one of the rainiest states in the nation. In eight states, late fall and winter months record peak rainfall.
To identify the states with the most rain, 24/7 Wall St. reviewed for each state average yearly precipitation from 1901 to 2000 using the Climate-at-a-Glance feature of the National Centers for Environmental Information produced by the National Oceanic and Atmospheric Administration (NOAA). We also reviewed for each state average monthly rainfall based on precipitation data collected from 1981 through 2010, also from NOAA. 100 years of data were not available for Hawaii, so its ranking is based on the average yearly rainfall over the 30 years through 2010.