NASA's water cycle research missions can be grouped into 3 major categories; Water Cycle, Energy Cycle, and Water and Energy Cycle Missions. By studying each and every variable of Earth's water and energy cycles, As Only NASA Can, a crucial understanding of the water cycle's effect on global climate is currently underway.
Home > Holiday and Occasions > Fall - Autumn > When is the first day of Fall - Autumn 2017? When is the first day of fall 2017? In 2017, fall begins on September 22rd (at 20:02 UTC) for countries in the Northern Hemisphere. The date may be different for you based on what time zone you live in. This chart reflects the UTC time zone. Note: Equinoxes are opposite on each side of the equator.
Seasons are fundamental to how we understand the climate and the environment, but for hundreds of years academics have argued that their specialist field is the one which defines official start of autumn. In meteorological terms autumn begins on September 1, as each season is defined as a three-month period. Astronomers base the date of the seasons upon celestial events, in this case the autumnal equinox, when night and day are roughly equal length.