Equinoxes and solstices

What they mean

At the equinoxes the sun is directly above the equator and day and night are close to equal everywhere. The June solstice is the longest day in the northern hemisphere and the shortest in the southern; the December solstice is the reverse. Astronomical seasons begin at these moments, while meteorologists use whole months (for example 1 March for northern spring).

Times are calculated to within about a minute.