LogFAQs > #973242349

ParanoidObsessive posted...

As others have pointed out, it's technically both, since the official start of summer is the 20th/21st. But people usually round that off so that June/July/August is summer, Sep/Oct/Nov is autumn, Dec/Jan/Feb is winter, and March/April/May is spring.

Pretty much this, though in practice Spring weather often extends well into June, Summer weather often extends well into Sept/Oct, and Winter weather usually takes over part of November and often lasts until early April. Those three-month divisions make intuitive sense and are how I tend to think of the seasons falling, but the reality of the matter is that seasonal weather patterns vary quite wildly from place to place and even year to year.

bsp77 posted...

This is actually the correct answer in terms of meteorology. The seasons we typically use are based on astronomy and not weather. Why would summer begin on the longest day of the year? It makes no sense.

Because astronomy is consistent and weather is not. Were seasons based entirely on weather, the start date would vary wildly and you'd really only be able to pin it down a couple weeks after the fact when you confirmed that that was the first day that the 7-day average temperature exceeded whatever arbitrary threshold you decided on. That's not really conducive to throwing a party to celebrate the start of the season/end of the previous one, so people chose something a little more concrete, even if they still had to make some adjustments to their seasonal behaviours based on what the current weather was doing..