Earliest sunset of the year is today - more than a week before the solstice A day. measured on a clock, is exactly 24 hours in length but a 'solar day' is not. A solar day is measured by the spin of the earth and is the time it takes for the sun to return to the meridian you are on. Solar noon, therefore, is the instant that the sun reaches its highest point in the day. Today in the UK the sun reached its noontime position at 11.54 am However on December 21, the winter solstice, the sun will reach its noontime position at 11.58 am This, then, means that the sunset today will occur at 3.51 pm, but on the solstice the sunset will occur three minutes later, at 3.54 pm. The dates of the earliest sunrise and sunsets vary by latitude. Parts of North America, southern Europe and India have already had their earliest sunsets.