When Is Summer? It Depends on Your Hemisphere

Summer occurs at opposite times of year in the Northern and Southern Hemispheres due to Earth's 23.5° axial tilt.

Northern Hemisphere (June–August)

• Astronomical Summer: June Solstice (~June 20–21) to September Equinox (~Sept 22–23).
• Meteorological Summer: June 1 – August 31 (for climate statistics).
• Includes: North America, Europe, Asia, northern Africa.

Southern Hemisphere (December–February)

• Astronomical Summer: December Solstice (~Dec 21–22) to March Equinox (~Mar 20–21).
• Meteorological Summer: December 1 – February 28/29.
• Includes: Australia, New Zealand, South America (south of Amazon), southern Africa.

Equatorial Regions

Near the equator, seasons are less defined—typically "wet" and "dry" seasons rather than summer/winter.

Why the Difference?

Earth's axis tilts toward the Sun during each hemisphere's summer, bringing longer days, higher sun angle, and more intense heating. The solstices mark maximum tilt toward/away from the Sun.

So when it's summer in New York, it's winter in Sydney—and vice versa.