Season Calculator

1. Choose your hemisphere, northern or southern.
2. Pick a date with the date picker.
3. Read the season it falls in.
4. See the approximate date range of that season.

Here is what each result means:

The four seasons, spring, summer, autumn and winter, are set by the position of the Earth in its orbit around the Sun. Astronomically, each season begins at an equinox or a solstice: spring at the March equinox, summer at the June solstice, autumn at the September equinox and winter at the December solstice, for the northern hemisphere.

Because the seasons come from the tilt of the Earth's axis, they are reversed between the two hemispheres. When it is summer in the north, it is winter in the south, and the same date can be in opposite seasons depending on where you are. That is why this calculator asks which hemisphere you mean.

The astronomical dates are the traditional ones, but they shift by about a day from year to year because the calendar and the orbit do not line up exactly. Many weather services instead use meteorological seasons, which start on the first of a month, to make record-keeping simpler. This tool uses the astronomical boundaries.

It compares your date against the equinox and solstice boundaries, then adjusts for the hemisphere.

1. Your date is checked against the northern-hemisphere season boundaries.
2. If you chose the southern hemisphere, the season is flipped to its opposite.
3. The matching season and its date range are shown.

For other calendar tools, see the day of the week calculator and the week number calculator.

Take 15 July.

Result: in the northern hemisphere that is summer, which runs from about 21 June to 21 September. In the southern hemisphere the same date is winter, because the seasons there are reversed.

Astronomical seasons for the northern hemisphere, with the southern hemisphere reversed.

Each season starts at an equinox or solstice. The dates given are typical; the exact moment moves by up to a day each year, so a date right on a boundary can vary between years.

There are two common ways to define the seasons.

Meteorological seasons group whole months, so northern summer is June, July and August. This makes weather records easier to compare year to year. The astronomical system used here follows the Earth's orbit and starts each season a few weeks later.

The Hemisphere

Seasons are reversed north and south, so the same date can be summer or winter.

The Date

The season depends on where the date falls between the equinoxes and solstices.

The Year

The exact boundary moves by about a day each year as the orbit and calendar drift.

Planning

Check the season for a date when arranging travel or events.

Cross-hemisphere

See what season a date is in another part of the world.

Learning

Understand how equinoxes and solstices set the seasons.

1. Forgetting the Hemisphere

The same date is opposite seasons north and south, so always set the right hemisphere.

2. Mixing the Two Systems

Astronomical seasons start weeks later than meteorological ones, so the two can disagree near a boundary.

3. Assuming Fixed Dates

Equinox and solstice dates move by about a day each year.

4. Ignoring the Tropics

Near the equator the four-season model does not really apply; wet and dry seasons are more relevant.

5. Expecting Exact Weather

Seasons are calendar boundaries, not a guarantee of any particular weather on a date.

The season follows the standard astronomical boundaries, which shift by about a day each year.

It depends on the hemisphere. In the north, 15 July is summer; in the south it is winter. Pick a date and hemisphere and the calculator shows the season.

In the north, spring starts at the March equinox, summer at the June solstice, autumn at the September equinox and winter at the December solstice.

Because the Earth's tilt points the two hemispheres toward the Sun at opposite times of year. When the north tilts toward the Sun it is summer there and winter in the south.

Astronomical seasons start at the equinoxes and solstices. Meteorological seasons start on the first of a month, grouping whole months, which weather services prefer.

Slightly. The equinoxes and solstices move by up to a day between years because the calendar and the Earth's orbit do not line up exactly.

The four-season model does not fit the tropics well. Places near the equator usually have wet and dry seasons rather than spring, summer, autumn and winter.

The astronomical system, based on the equinoxes and solstices. You can compare it with meteorological seasons, which start on the first of the month.

No. Seasons are calendar boundaries tied to the Earth's orbit. Actual weather on any date depends on many local factors.

No. The calculation runs in your browser and nothing you enter is stored or sent anywhere, unless you choose Save, which keeps the result only on this device.

• Season (Wikipedia).
• Equinox (Wikipedia).
• Solstice (Wikipedia).