Summer 2026 in the U.S. starts on Sunday, June 21, 2026 and ends on Tuesday, September 22, 2026. This is the astronomical definition of summer, based on the solstice and equinox.

Quick Scoop

  • Start: June 21, 2026.
  • End: September 22, 2026.
  • Note: Some people use meteorological summer , which runs from June 1 through August 31.

Simple Table

Definition 2026 Dates
Astronomical summer June 21 to September 22
Meteorological summer June 1 to August 31
Astronomical summer is the one most people mean when they ask for the official start and end of summer in the U.S..