All of these changes are due to the simple fact that Earth equatorial plane is not in line with its orbital plane. The equator is tilted 23.5 degrees relative to Earth’s orbit. Were it not for this tilt, there would be no seasons. No hot summer nights, no ski season, no fall colors, no spring rebirth.

Thankfully, fall is here. Harvest is in full swing. Temperatures are dropping and the leaves are starting to change color.

In the southern hemisphere, however, seasons are reversed. As the noontime sun is sinking in our sky, it is climbing higher and higher ‘down under.’ Our days are shortening, their days are lengthening. Spring is beginning and light is returning to the south pole.

Whatever your preference in seasons, sports, foods, or outdoor activities, enjoy this day, the changing of the seasons.

Lammas is traditionally recognized as August 1st each year, and is celebrated by baking loaves of bread from the first wheat harvests. But there is a strong astronomical connection to this date as well.

Lammas is a cross-quarter day, marking the halfway point between the summer solstice in June and the autumnal equinox in September. Although we declare the beginning of each season by the associated solstice or equinox date, we begin to think about the changing of the season closer to the cross-quarter dates. Autumn may begin on September 22nd this year, but it is around the beginning of August that our thoughts and activities begin to switch from summer-mode to fall-mode. For many, school is beginning. For most others, back-to-school shopping is at least underway. Summer vacations are winding down. Harvest season is upon us and the canning of fruits and vegetables is about to begin. As the ‘dog days of summer’ set in, we even start hoping for cooler weather.

August 1st may be called the Day of Lammas, but the actual mid-point date will vary. For 2009, the summer solstice was on June 21st and the autumnal equinox will be on Sept. 22nd, so the actual cross-quarter date is August 6th.

You are more familiar with the other cross-quarter dates of the year than you may realize. Going backwards from Lammas on August 1st, halfway between the summer solstice in June and the spring equinox in March is May Day, on May 1st. Halfway between the spring equinox in March and the winter solstice in December is Groundhog Day, February 2nd. Halfway between the winter solstice in December and the fall equinox in September is Halloween, October 31st. It’s interesting that we don’t celebrate the astronomical season dates, but we do celebrate these midpoint dates: the cross-quarter days.