Meteorological vs. Astronomical Spring: What's the Difference?

Explaining the two different ways to define the start of the spring season.

Mar. 21, 2026 at 4:18pm

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The first day of spring was Friday, but for meteorologists, spring actually started at the beginning of the month. There is a difference between meteorological spring and astronomical spring, and this article explains the reasoning behind the two different systems.

Why it matters

Understanding the difference between meteorological and astronomical spring is important for properly interpreting weather data, climate statistics, and seasonal patterns that impact agriculture, commerce, and other industries.

The details

Astronomical spring is based on Earth's orbit around the sun and the alignment of the equinoxes and solstices, which can vary in date each year. Meteorological spring, on the other hand, is defined as the three-month period of March, April, and May, providing more consistent 90-day seasons for easier data analysis.

  • The first day of astronomical spring was Friday, March 21, 2026.
  • Meteorological spring began on March 1, 2026.

The players

Earth

The planet whose tilt and orbit around the sun define the astronomical seasons.

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The takeaway

The difference between meteorological and astronomical spring highlights how scientific and practical considerations can lead to different ways of defining the same natural phenomenon. Understanding these distinctions is crucial for properly interpreting weather data and climate patterns.