Climate change has increased pollen counts and the length of the pollen season, trends that are expected to continue through mid-century.
Spring is arriving earlier across the U.S. by an average of three days.
Foliage color and timing has been starting later, on average, in a warming world.
Scientists say increased CO2 emissions are making poison ivy worse.
The highlights of NOAA's 2013 Spring climate summary.
If it seems like autumn leaves are taking longer to change color, you're not imagining things. Over the past 25 years, the onset of autumn has shifted.
Online searches for the word"pollen" have gone through the roof this spring, and if you know anyone with seasonal allergies (and who doesn't?) this isn't surprising.
The Lower 48 as a whole had an average shift of "first leaf" from March 20 (1951-1980 average) to March 17 now (1981-2010 average): approximately 3 days earlier.