Autumn is one of the four seasons in the temperate zones of North America. It is the transition season from summer to winter and occurs during the months from September to December in the Northern Hemisphere (in the Southern it is Spring). During this season, the duration of daylight hours is noticeably reduced and the temperature is considerably cooled. However, the exact date of when autumn begins varies according to the location and the climate. In the United States, fall generally begins in late September.
Fall is defined as the time when the days and nights are the same length and the temperature drops drastically. The fall equinox is the point on the calendar when the sun crosses the celestial equator from north to south. It is also the time when the Harvest Moon appeared full for three consecutive days, preceding the official start of fall. In the Northern Hemisphere, meteorological fall officially begins in late-September.
The days and nights of autumn are defined by the fact that they are below 70 degrees Fahrenheit. For those who are unaware of the season's official beginning date, it is best to consult a meteorological calendar that include the equinoxes and solstices. These are a good place to begin planning for your fall vacation.
What is the official start of fall?
The meteorological calendar uses several different calendars to define the start of fall. The autumnal equinox is the time of year when the sun crosses the celestial equator from north to south. Historically, the season was preceded by the Harvest Moon, which appeared full for three days. According to the meteorological calendar, autumn begins on 22 September. The season starts on the autumnal equinox and ends on the winter solstice. The fall equinox is the first day of fall and occurs when the sun is shining directly over the equator. Meteorologists actually divide the year into four meteorological seasons, which are three months long.
