Today, September 1, marks the first day of meteorological autumn. For most people in the Northern Hemisphere, Autumn 2020 begins on Tuesday, September 22 and ends on Monday, December 21. But for many scientists, the end of August marks the end of their summer. Meteorologists and climatologists break the seasons down into groupings of three months based on the annual temperature cycle. In the world of meteorology and climatology, autumn includes September, October, and November; winter includes December, January, and February; spring includes March, April, and May; summer includes June, July and August. Because the seasons are based on months and not traditional astronomical ones, the length of the meteorological seasons is more consistent, averaging about 91 days per season. By following the civil calendar, meteorologists and especially climatologists can better calculate seasonal statistics from monthly ones.
While today marks the first day of meteorological autumn, we’re just starting the traditional busy part of hurricane season in both the Central Pacific and Atlantic hurricane basins. With 91 days left of hurricane season, some of the busiest days could be ahead of us. Traditionally, September 10 marks the busiest day of the Atlantic hurricane season, with the most hurricanes and tropical storms present that day when looking over the last 100 years. Activity remains high into October before tapering off in November. Hurricane season officially ends in both the Central Pacific and Atlantic basins on November 30.