Weather: Saturday will be first day of summer

It looks like we’re returning to some summerlike weather across the Inland Northwest. Readings were only in the 60s late last week and in the 50s on Tuesday, thanks to a series of chilly storm systems. By this weekend, afternoon high temperatures are forecast to finally warm into the 80s across many locations. These readings arrive just in time for the first day of summer, which begins at 3:51 a.m. on June 21.

 On that day, the sun angle is the highest in the sky and the Northern Hemisphere will experience the highest number of daylight hours. The exact hours and minutes may have some slight variances across a number of towns and cities, as some areas will have their longest day near, but not on, the first day of summer due to differences in elevation, terrain and proximity within the time zone.

Many of us look forward to this longest day, the summer solstice, which is 15 hours, 59 minutes and 45 seconds in Spokane on June 21. After an often chilly winter and a sometimes wet spring, the summers in this area are usually glorious.

On June 21, the sun’s rays will be directly overhead at 23.5 degrees north latitude in the Northern Hemisphere, called the Tropic of Cancer. By the first day of fall, the sun’s rays will be directly over the equator and then at the Tropic of Capricorn, 23.5 degrees south latitude in the Southern Hemisphere on our first day of winter. (The seasons are reversed in the Southern Hemisphere, with winter beginning in June on the solstice and summer beginning in December.)

As our planet orbits the sun, we are actually farther away from our star by about 3 million miles at this time of year than during our winter season. The Earth’s tilt is what contributes to our seasons. Right now, our planet is tilted toward the sun in the Northern Hemisphere and away from the sun in the Southern Hemisphere. During our winter, it’s the opposite, as we’re tilted away, so the sun angle is much lower and we’re still experiencing those cold temperatures despite being about 3 million miles closer to the sun.

Correction: There was a typographical error in last week’s column. Spokane’s lowest temperature was actually minus 30 degrees on Jan. 15, 1888. Thanks to all who emailed asking about this.