From Friday, it is exactly five weeks until June 21, the summer solstice, but some of the most cherished features of summer are already here: the long, long days.

As many of the year’s longest days occur before the solstice as after it. Friday began our annual 10 weeks of maximum daylight.

The time in Washington on Friday between sunrise and sunset was 14 hours 21 minutes. That illuminated period reaches its peak on the day of the solstice, June 21, extending to 14 hours 54 minutes.

The length of daylight then declines, and for us on July 26, five weeks after the solstice, it falls back to 14 hours 21 minutes, the same as Friday.

However, although the duration of daylight is the same as we approach the solstice and as we move away from it, the times of sunset and sunrise are not the same day. Both sunrise and sunset are later after the solstice. This results in part from varying speeds of the earth on its elliptical orbit around the sun. It is also an effect of the tilt of the earth’s axis.

In some ways, long days before the solstice may seem even more pleasant than after it. They are usually cooler. Friday’s normal high here was 76; the normal high 10 weeks from now is 88.