It's the day with the most hours of daylight in the year, traditionally seen as the beginning of summer.
It marks the day when the Northern hemisphere is as its maximum tilt to the sun, leading to 17 hours of daylight.
This year's is extra special, because, for the first time since 1967, we'll also have a 'Strawberry Moon'.
Also known as a Honey Moon, a Hot Moon or a Rose Moon, it's when June's full moon happens on the solstice.
It's generally a once-in-a-lifetime occurrence, happening every 50 to 70 years, but despite the name, it won't appear to be red or pink.
It's name is derived from the Native American belief that the moon marks the start of the relatively-short strawberry-picking season.
The moon’s low angle means its light must go through thicker air, which can lead to amber skies as it rises and falls.
Astrologers claim the phenomenon is ripe with significance, but still can’t predict it without the help of actual calculations.
Sunset is due at 9.48pm tonight, and, if the sky is clear enough, you should look out for the Strawberry Moon in the couple of hours after that.
If you miss tonight's Strawberry Moon you'll have to wait 46 years before you can see a full moon on the summer solstice, with the next one not due until June 21, 2062.
* We'd love to see any pictures you get of the Strawberry Moon. Send them to [email protected], or share them with us via our Facebook or Twitter pages.