Summer can “start” on two different dates, depending on which definition you use:

  • Astronomical summer (Northern Hemisphere): It starts at the summer solstice, when the Sun reaches its northernmost point in the sky. In 2026, that’s Sunday, June 21, 2026.
  • Meteorological summer (Northern Hemisphere): For weather and climate stats, summer is simply the months of June, July, and August , so it starts June 1 every year.

Many people also use cultural “markers” instead of astronomy:

  • In the US, some treat Memorial Day weekend as the “kickoff” to summer, even though it’s still technically spring.
  • Others just say summer is June–August or even mid‑April to late September, based on how it feels where they live.

So if someone asks “when does summer start?”, the precise scientific answer is the summer solstice in late June , but a lot of daily life, weather stats, and forum chatter treats June 1 (or even Memorial Day) as the informal beginning.

TL;DR:

  • Official (astronomical): around June 20–22 (e.g., June 21, 2026).
  • Meteorological: June 1.
  • Everyday life: often Memorial Day or just “once it’s hot and school’s out.”

Information gathered from public forums or data available on the internet and portrayed here.