The start of fall can be perceived in different ways, influenced by scientific definitions and regional climate patterns. Understanding these distinctions helps clarify when the season truly arrives, especially in a state like Mississippi.
Astronomical Fall Start
Astronomical fall marks its beginning with the autumn equinox, a precise celestial event. This occurs when the Earth’s axis is neither tilted towards nor away from the sun, resulting in roughly equal day and night across the globe. This event typically falls around September 22nd or 23rd each year, though the exact date can shift slightly due to the Earth’s elliptical orbit and leap years.
This definition is a fixed, universal standard based purely on celestial mechanics and the Earth’s position relative to the sun. It provides a consistent global marker for the change of seasons, regardless of local weather conditions.
Meteorological Fall Start
Meteorological fall, in contrast, adheres to a fixed calendar period for consistent data collection. This definition designates September 1st as the start of autumn, concluding on November 30th. This three-month division aligns with the annual temperature cycle, grouping months with similar average temperatures together.
Meteorologists and climatologists use these standardized three-month segments to track seasonal weather patterns and conduct statistical analyses. This approach provides a uniform framework for comparing climate data year after year, aiding in forecasting and climate research.
Mississippi’s Autumnal Nuances
While astronomical and meteorological definitions provide precise dates, the true “feel” of fall arrives differently in Mississippi. September often continues the warmth of summer, with high temperatures frequently reaching into the upper 80s Fahrenheit and humidity remaining elevated. The transition to cooler, drier air typically begins subtly in October.
Significant cooling usually becomes more consistent in late October and November, when daytime temperatures settle into the 60s and 70s Fahrenheit. This delayed cooling means that traditional autumn activities, like enjoying crisp air, often occur later in the season compared to northern regions. Mississippi’s extended warm period also impacts foliage changes.
Many of the common tree species in Mississippi, such as various oaks and pines, do not display the vibrant, widespread color changes seen in other parts of the country. When foliage does change, it tends to be later in the year, typically in mid to late November, and often less intense. The longer growing season and specific tree types contribute to this distinct autumnal experience.