Seasons of the year: dates and times

Seasons of the year: dates and times: what it is for

See the exact day and time of the March and September equinoxes and the June and December solstices of any year, with the start of spring, summer, autumn and winter in the Northern or Southern Hemisphere, the length of each season and how many days are left until the next one. Times are shown in the time zone you choose, calculated with Jean Meeus's algorithm, accurate to about 1 minute.

The calculations run in your browser, without sending anything to a server.

How to use

1. Enter the year.
2. Choose the hemisphere and time zone.
3. See the dates, times and length of the seasons.

When to use it

• Knowing when summer or winter starts.
• Geography and science lessons.
• Planning trips and seasonal events.

Frequently asked questions

When do the seasons start?

In the Northern Hemisphere, spring starts at the March equinox (around March 20), summer at the June solstice (around June 21), autumn at the September equinox (around September 22 or 23) and winter at the December solstice (around December 21 or 22). In the Southern Hemisphere, the seasons are the opposite.

Why do the dates change from one year to the next?

Because the solar year is about 365 days and 6 hours long. Each year, the equinoxes and solstices happen about 6 hours later, and the extra day of leap years pulls the dates back. That is why the start of the seasons moves between two or three calendar days.

How are the times calculated?

With the algorithm by astronomer Jean Meeus (Astronomical Algorithms, chapter 27), which uses a formula for the mean instant and 24 periodic correction terms. The error is about 1 minute in the 20th and 21st centuries.

Is it really free?

Yes, 100% free. No sign-up, no subscription and no usage limits. All Tools123 tools are free and run right in your browser.

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