It is the last day of the spring!
This is a common date for the Summer Solstice in the Northern Hemisphere. In the Northern Hemisphere…on: June 20, 2008 at 7:59 PM EDT; and in the UK on June 20, 2008 at 23:59 UTC.
The word solstice is from the Latin solstitium, from sol (sun) and stitium (to stop), reflecting the fact that the Sun appears to stop at this time (and again at the winter solstice). In temperate regions, we notice that the Sun is higher in the sky throughout the day, and its rays strike Earth at a more direct angle, causing the efficient warming we call summer. In the winter, just the opposite occurs: The Sun is at its southernmost point and is low in the sky. Its rays hit the Northern Hemisphere at an oblique angle, creating the feeble winter sunlight.