About this tool
The Summer Countdown shows exactly how much time is left until the start of summer, updating in real time.
When does summer start?
This calculator counts down to June 21, the approximate date of the June solstice, which marks the astronomical start of summer in the Northern Hemisphere (and the start of winter in the Southern Hemisphere). The exact date of the solstice can shift by a day depending on the year.
Astronomical vs. meteorological summer
Astronomers mark the start of summer by the solstice, while meteorologists use a simpler system based on the calendar month, defining summer as June, July, and August in the Northern Hemisphere. That's why you may see two slightly different "first days of summer" depending on the source.
Why use a countdown?
Whether you're planning a vacation, a school break, or simply looking forward to warmer weather, a countdown makes it easy to see exactly how many days are left.