What are the starting and ending dates of seasons in the US?

I think the seasons start on or around the 21st of the months of september (fall), december (winter), march (spring), and june (summer).

In the States, the seasons begin on the solstices and the equinoxes. The summer solstice (June 21 or 22) marks the day of the year when there is most sunlight (longest day). Winter begins on the winter solstice (Dec 21/22), marking the day of the year with the least amount of sunlight. Equinoxes (meaning equal night) are the days of the year that have equal hours of day and night. The autumnal equinox falls on September 21 or 22, and the vernal equinox, which marks the onset of spring, falls on March 21 or 22.

So from June 21 (the longest day), the number of minutes of daylight decreases, until the autumnal equinox, where there are now equal amounts of day and night. From that point on there are more hours of darkness than of light, peaking on the winter solstice (the shortest day). From that point on, the number of minutes of sunlight increases. In March, day and night are equal again, and then there are more minutes of light all the way until the summer solstice once again.

And yes, the situation is reversed in the southern hemisphere, so when we in the States are having summer, you (Australia) are having what we call the Austral Winter.

Thanks brownlemur, just the answer I was looking for.

And none of this is actually official in any capacity I know of; it’s just that US calendars will say “First Day of Winter” on Dec. 22, “First Day of Spring” on March 22, “First Day of Summer” on June 22, and “First Day of Fall” on September 22.

Which makes concepts like “midsummer day” a little bit confusing, since the calendar says it’s the first day of summer…. and generally, the first snowfall, in regions that actually get snow, is long before 12/22.

i’d like to second cwillbur—seasons are subjective and will vary by longitude.