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.
When does spring officially start? How do we define the seasons? It depends on whether you are referring to the astronomical or meteorological spring. When we talk about the beginning of winter or any other season, we are usually talking about the day in our calendars that mark this date. This refers to the astronomical seasons which are a result of the Earth's axis and orbit around the sun.