Change in allergy season length in select cities
Days between last freeze in spring and first freeze in fall; 1970–2022
-15
0
+15
+30
+60
+100
Map of change in allergy season length by cities. For 73 cities, allergy season lasted up to 15 days longer; for 69 cities, the season was 16 to 30 days longer; for 26, the season was 1 to 2 months longer; and for 4 cities, the season increased by more than 2 months. For 30 cities, the season got shorter.
