If you aren't looking at a calendar, you might determine the start of autumn through —the study of periodic biological phenomena. This is "nature’s autumn," and its timing varies based on your specific climate and latitude. Signs include:
This definition is much easier for record-keeping and forecasting because the dates never change, regardless of the Earth's tilt or orbit. 3. Phenological Autumn (The Nature approach) when is autumn
Understanding when autumn starts helps with everything from agriculture to energy management. Farmers use these dates to time their final harvests, while city planners use them to prepare for increased heating demands and leaf clearance. If you aren't looking at a calendar, you
You may notice birds migrating south, squirrels frantically gathering nuts, or insects disappearing. You may notice birds migrating south, squirrels frantically
For most people, the official start of autumn is the . This is the moment when the sun crosses the celestial equator, making day and night nearly equal in length. Northern Hemisphere: Usually occurs on September 22 or 23 . Southern Hemisphere: Usually occurs on March 20 or 21 .