Summer Countdown 2027

Summer 2027 begins at the June solstice, the longest day of the year in the northern hemisphere. Depending on the year it falls on 20 or 21 June. The countdown above targets the exact moment the Sun reaches its highest point above the equator.

How much daylight? It depends entirely on latitude. On that day London gets about 16 h 38 of daylight, New York 15 h 06, Edinburgh 17 h 36. North of the Arctic Circle the Sun does not set at all: the midnight sun.

The longest day is not the hottest. Temperature records come in July or August, four to eight weeks later. Oceans and soil take weeks to release the heat they have absorbed, a lag known as seasonal thermal inertia. The solstice is the peak of sunlight, not the peak of heat.

From here the days shorten — a few seconds at first, then faster and faster until the September equinox.

Two summers coexist: meteorologists start theirs on 1 June, to work with whole three-month blocks. This countdown tracks the astronomical one.