USA NPN National Phenology Network

Taking the Pulse of Our Planet

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How does the spring of 2017 stack up to the recent past?

March 20th is the Spring Equinox, which marks the official start of spring on your calendar. This year, the biological start of spring occurred much earlier than average in a large part of the Great Basin, Great Plains, Midwest, and mid-Atlantic.  Spring also arrived 2-3 weeks early across much of the South, although it typically has arrived by March 20th and therefore is represented as "average conditions" on this map. In the Great Basin and central Great Plains, spring arrived even earlier than 2012, a recent year with a very early start to spring. In Midwest states such as Iowa, Illinois, and Michigan, spring this year is arriving early, but not as early as in 2012.

Spring leaf index Mar 20 2017 compared to 2012 and average


March 2012 broke numerous records for warm temperatures and early flowering in the United States (Ault et al. 2013). As of February 27, 2017, the 2017 is shaping up to be two to three weeks earlier than 2012 in many parts of the country.  

Leaf index for 2017 compared to 2012


Ault, T.R., Henebry, G.M., de Beurs, K.M, Schwartz, M.D., Betancourt, J.L., Moore, D. 2013. The false spring of 2012, earliest in North American record. EOS, DOI 10.1002/2013EO200001.