Spring is a critical season for water the Salt Lake Valley. On average, May, April, and May are the three wettest months of the year, as shown by the blue bars in the graph below.
|Climatological and 2011-12 water year precipitation at the Salt Lake|
International Airport. Source: NWS and Western Region Climate Center
The water cycle is affected not only by precipitation, but also evaporation and transpiration by plants, which we refer to collectively as evapotranspiration. Evapotranspiration is influenced by a number of factors (sun, wind, etc.), but one of the most important is temperature. All else being equal, higher temperatures mean greater evapotranspiration rates and faster drying of the soils. At the Salt Lake City International Airport, March was 5.4ºF above average, April 3.4ºF above average, May 1.7ºF above average. Although we've had a couple of cold spells, June is running just above average thus far too. Thus, the soils this spring are drying more quickly.
Climate model precipitation projections for the middle 21st century vary over northern Utah, but most call for May and June to be a bit drier than they were in the later half of the 20th century.
|Source: Thomas Reichler, University of Utah|
For more discussion, see section 5 of our climate report to former Gov. Jon Hutsman Jr.'s Blue Ribbon Advisory Council on Climate Change.