Wednesday, June 21 marks the summer solstice, also known as the longest day of the year when it comes to the amount of daylight that we see.
When the summer solstice occurs, the northern hemisphere is tilted as far towards the sun as possible, leading to the maximum amount of daylight hours.
In fact, more than three hours of daylight are gained in the six months between the winter and summer solstice. For context, on the day of the winter solstice last year, the amount of daylight received in San Antonio was 10 hours, 15 minutes and 35 seconds. Fast forward six months, and the amount of daylight received on the day of the summer solstice measured 14 hours, 1 minute and 54 seconds.
Going forward from here, the daylight amount will start to decrease all the way up to the next winter solstice, which will occur on December 21, 2023. And thus the cycle continues.
So how will this affect our sunrise and sunset times in South Central Texas?
In a general sense, sunset times will be at their latest in the immediate days ahead, and will slowly start to get earlier and earlier all the way up to the beginning of December.
Check out the table for San Antonio below:
| Day | Sunrise Times in San Antonio | Sunset Times in San Antonio |
|---|---|---|
| June 21, 2023 (Summer Solstice) | 6:34 AM | 8:36 PM |
| July 1, 2023 | 6:37 AM | 8:37 PM |
| August 1, 2023 | 6:54 AM | 8:26 PM |
| September 1, 2023 | 7:11 AM | 7:56 PM |
| October 1, 2023 | 7:27 AM | 7:19 PM |
| November 1, 2023 | 7:46 AM | 6:47 PM |
| November 5, 2023 (Daylight Saving Time Ends) | 6:49 AM | 5:44 PM |
| December 1, 2023 | 7:10 AM | 5:34 PM |
| December 21, 2023 (Winter Solstice) | 7:24 AM | 5:39 PM |
| December 31, 2023 | 7:28 AM | 5:45 PM |
After looking at this table you may be asking — why doesn’t the earliest sunset occur on the winter solstice, when the northern hemisphere is tilted the farthest away from the sun?
It all has to do with the fact that time measured by the sun is not exactly the same as time measured by our clocks.
After the sun rises in the east and before it sets in the west, it passes over an invisible line that runs from north to south known as the meridian. This is when it is positioned highest in the sky, and when it reaches “solar noon.” The time between one solar noon to the next is the “apparent solar day” and can be measured by a sundial.
We would often think that the length of a solar day would be exactly 24 hours, but that’s not the case. While the Earth’s spin is never more than a few milliseconds faster or slower in a given day, a solar day can be up to 22 seconds shorter or 29 seconds longer than a 24-hour period.
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