How Many Days Until Summer?

Two Solstices, One Tool

Astronomical summer starts on a different calendar day depending on which hemisphere you're in: June 21 for the Northern Hemisphere, December 21 for the Southern Hemisphere. Both dates mark a solstice — the point in Earth's orbit where that hemisphere is tilted most directly toward the sun and gets its longest day of the year. Switch the radio button above and the countdown recalculates against whichever date applies. In 2026 the Northern Hemisphere solstice falls on a Sunday (June 21); the Southern Hemisphere one falls on a Monday (December 21).

Why the Date Isn't Always the 21st

June 21 and December 21 are typical, but the solstice can land on the 20th, 21st, or occasionally the 22nd depending on the year — a calendar year doesn't divide evenly into the time Earth actually takes to orbit the sun, so the exact moment drifts slightly year to year. This tool uses the 21st as a fixed reference, which is accurate most years but can be off by a day in others.

Astronomical vs. Meteorological Summer

This countdown tracks astronomical summer, tied to the solstice. Meteorologists use a simpler system based on the calendar month: in the Northern Hemisphere, meteorological summer runs June 1 through August 31 regardless of where the solstice falls. If you're planning around typical weather rather than the sun's position, meteorological summer starts about three weeks earlier than what this tool shows.

What This Tool Doesn't Do

The countdown reads your device's clock and can't be pointed at a custom date — it always targets the next solstice for whichever hemisphere you select. If your device's date, time, or time zone is set incorrectly, the countdown will be off by the same amount.