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The first of March marks the start of spring for meteorologists in the Northern Hemisphere, even though astronomical spring comes later in the month on the spring equinox. Meteorologist Caitlin Kaiser explains the differences between the two and why meteorologists follow a different seasonal calendar.

Why it matters

The distinction between meteorological and astronomical spring is important for weather forecasting and reporting, as it allows meteorologists to align their seasonal data and predictions with the typical weather patterns observed on the ground.

The details

Meteorological spring begins on March 1 each year, while astronomical spring is determined by the position of the Earth in relation to the sun and occurs on the spring equinox, which typically falls around March 20-21. Meteorologists prefer to use the March 1 date as it better matches the weather patterns they observe, with temperatures warming, precipitation increasing, and vegetation starting to bloom.

• Meteorological spring begins on March 1 each year.
• Astronomical spring occurs on the spring equinox, typically around March 20-21.

What they’re saying