You probably won't notice, but daylight starts getting shorter after today. The Summer Solstice occurs this evening at 10:31 p.m. Central Daylight Time. You probably won't notice right away because the length of day is only shortened by a few seconds per day for the first couple of weeks after the Solstice. The rate of change increases to around three minutes per day around the time of the Autumnal Equinox. Another reason you won't notice is that the sunsets actually continue to happen a few seconds later per day later through Friday, June 25, and the earliest sunrise happened back on June 15.

These minor irregularities are due to the fact that our clocks are set for 24 hours, but the actual solar day length varies throughout the year. The solar day, which is the difference from high noon one day to the next, varies because Earth travels in an elliptical orbit around the Sun at a slightly variable speed.

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