Sweat season is finally here.

The summer solstice — the annual moment at which the sun is the highest it ever gets in the sky — occurs Thursday at 6:07 a.m. ET. This time also marks the beginning of astronomical summer up here in the Northern Hemisphere.

However, realistically, it's been summer for three weeks: Meteorologists consider summer to be the hottest three months of the year – June, July and August – which in terms of weather for those of us down here on Earth is more realistic than late-June to late-September.

And this year, the hot weather got a jump start in May, as the U.S. sweltered to its warmest May since records began in the late 1800s.

Looking ahead, if you like the heat, you're in luck: The forecast for the next few weeks shows warmer-than-average temperatures for nearly the entire nation, according to the Climate Prediction Center.

Also, on average, there is a one month lag between the solstice and peak summer temperatures, according to climatologist Brian Brettschneider.

Specifically, the summer solstice is the moment when the sun is directly above the Tropic of Cancer. This is the farthest north the sun ever moves in the sky, which is why the days close to the solstice have the most daylight of any days of the year.

People in Anchorage, Alaska, for example, will get 19 hours of daylight, while those in Seattle and New York City will see more than 15 hours. Los Angeles, Dallas and Atlanta will see more than 14 hours of daylight, while Miami and Honolulu will see less than 14 hours.

Some people call it "the longest day," but it's actually the day with the most daylight, to be precise, since every "day" has 24 hours.

The amount of daylight will stay about that length for a few more days before slowing shrinking each day until the winter solstice in late December.

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Many people around the world celebrate the summer solstice with music and festivities. In England, hundreds will travel at the ancient site of Stonehenge to celebrate the first day of summer. Solstice celebrations there have been going on for thousands of years.

Also Thursday: It's the winter solstice in the Southern Hemisphere, meaning it's going to start getting colder for the 12 percent of the world's population that lives down there.

Contributing: Chuck Campbell, Knoxville News Sentinel