The solstice | How much longer is the longest day?

What would you do with two extra seconds of daylight? Toss a Frisbee? Dive into a swimming pool? Glance at Mount Rainier? Or just pop open a cool one?

Whatever it is, get ready. Thursday is the summer solstice in the Northern Hemisphere, when Seattle will have 15 hours, 59 minutes and 31 seconds of daylight — a full two seconds more than today, according to timeanddate.com. Starting summer with the year's longest day may seem like beginning a sumptuous meal with dessert, but it's an astronomical fact of life: Our days get warmer in July and August, but they also get shorter. So set out your jogging shoes or fishing gear; you don't want to miss that 5:11 a.m. sunrise.

On paper, anyway: Summer officially arrives at 11:06 a.m. Thursday, says the Weather Service. But web-footed locals, remembering too many rained-out June events, will swear summer really doesn't hit here until sometime after the Fourth of July.

Oh, say, you may see, by the dawn's early light: Lois Woehrmeyer flinging tennis balls to her canine companions in the off-leash area at Seattle's Magnuson Park.

The park opens at 4 a.m., and it's not unusual for Woehrmeyer to be there by 5, exercising her Australian shepherd, Heidi, and a neighbor's dog, Rocky, "a mix of beagle and we-don't-know-what-else."

Even though Woehrmeyer is retired, she enjoys hitting the park early, especially this time of year. "The dogs couldn't care less; they can catch balls in the dark. But I like not having to follow them around with a flashlight."

Other haunts of some of the earliest-risers: the boat launch at Shilshole, where anglers embark on pre-dawn fishing trips; the path at Green Lake, where cars dot the parking lots by 4 a.m. and Seattle's municipal golf courses, where summer duffers tee off as early as 5:30 a.m.

Could too much daylight be messing with your body clock?

You know the feeling: The alarm clock says you have to get up at 5 a.m., but you can't fall asleep when there's light pouring in your window well past 10 p.m.

"Light has a powerful influence on the body's internal sleep-wake rhythm," said Dr. Vishesh Kapur, director of the UW Medicine Sleep Disorders Center. It's natural for the late-evening light to keep us awake, he said, but our bodies still want seven to eight hours of sleep.

If you feel more fatigued during the day, particularly about 1 p.m., you may be experiencing sleep deprivation. Possible remedies: Wearing sunglasses into the evening, putting heavier curtains on your bedroom windows or — and you may have to work this out with the boss — taking an early-afternoon nap.

Something for everyone: The solstice means lotsa stuff to lotsa people, from June brides planning the perfect wedding to cyclists who disrobed for last weekend's Fremont parade to New Agers, Wiccans, Pagans and Druids getting in touch with the forces of the universe.

"The sun symbolizes enlightenment and knowledge, shedding light and imparting wisdom," said Mark Magill, member of "Circle of Coll," a Seattle-area Druid group planning a brief observance. Magill, who goes by the name "Moss" in the group, recently returned from a pre-solstice event at Stonehenge in England.

Among this country's noted solstice observances is the annual eight-day "Pagan Spirit Gathering" attracting hundreds to a campground in Southeast Ohio.

Animals, too, enjoy the long days. Any parent who's had trouble calling kids in from the rosy twilight can understand a summertime challenge facing keepers at Woodland Park Zoo, who usually use dinner to get animals to come in for the night, for safety and security reasons.

"Gorillas, orangutans, monkeys and lions, in particular, are reluctant to come in for their evening meal, preferring to stay outside and lounge in the long grass as long as possible," said Dana Payne, a zoo curator. So staffers wait out their charges or, depending on the species, leave them outside.

And Payne offers this tip to summertime zoo-goers: The final hour of the day, after gates close at 6 p.m. and visitors are asked to leave at 7, can be the least-crowded time and a good chance to see animals that prefer to lie low during the heat of the afternoon.

The late-late show: If you love late sunsets and early dawns, hop a plane to Fairbanks, Alaska, where the sun stays up until 12:47 a.m., then dips below the horizon and pops back up at 2:58 a.m.

To bask in the night light, Fairbankers will gather Thursday for the 102nd annual "Midnight Sun" baseball game, which begins at 10:30 p.m. and breaks at midnight for the singing of the Alaska Flag Song, to be performed this year in the native Arctic Inupiat language.

But before you get too jealous of our northern friends' abundant daylight, consider the flip side: On the winter solstice in December, the Fairbanks sun is up for just 3 hours and 42 minutes.

Summer sickness? People who find they can't enjoy a long summer day while stuck at their desks might view this as a great — albeit slightly suspicious — time to call in sick.

While we, of course, would never actually endorse such behavior, we note author Ellie Bishop covers this ground in "The Sick Day Handbook: Strategies and Techniques for Faking It."

Among her suggestions: Don't discuss anything you may have to prove, such as doctors' visits or trips to the emergency room. Do shout for a few minutes before calling in, to give your voice that hoarse, sore-throat quality.

And choose an illness that won't invite a lot of questions. "Mention an IBS (irritable-bowel syndrome) flare-up," she suggests. "No one will ask you a thing."

Seattle Times news researcher Miyoko Wolf contributed to this report.

Jack Broom: 206-464-2222 or jbroom@seattletimes.com