Data Snapshots

Maps
Description
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Difference from Average - Monthly
Was the month drier or wetter than usual?  

Colors show where and by how much monthly precipitation totals differed from average precipitation for the same month from 1981-2010. Green areas were wetter than the 30-year average for the month and brown areas were drier. White and very light areas had monthly precipitation totals close to the long-term average. 

Where do these measurements come from?  

Daily measurements of rain and snow come from weather stations in the Global Historical Climatology Network. Volunteer observers or automated instruments gather the data and submit it to the National Center for Environmental Information (NCEI). After...

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About This Date: 
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