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Worked Examples
- 1.Day 62 is before day 80 (spring equinox)
- 2.Season: Winter (code 1)
- 3.Days into winter: 62 + 10 = 72 days (winter started at day 355)
- 4.Season progress: 72 / 90 = 80%
- 5.Days until spring: 80 - 62 = 18 days
Day 62 (March 3) is in winter, 72 days into the season (80% complete). Spring begins in 18 days.
Understanding Astronomical Seasons and Their Dates
Formula
The four astronomical seasons in the Northern Hemisphere are defined by the solstices and equinoxes: Spring begins around March 20-21 (vernal equinox), Summer around June 20-21 (summer solstice), Fall around September 22-23 (autumnal equinox), and Winter around December 21-22 (winter solstice). These dates shift slightly year to year but follow a consistent pattern.
This calculator uses day-of-year values based on approximate equinox and solstice dates: Winter starts at day 355 (Dec 21), Spring at day 80 (Mar 21), Summer at day 172 (Jun 21), and Fall at day 266 (Sep 23). It shows which season you are in, how far through it you are, and when the next season begins. Note that meteorological seasons differ, starting on the first of March, June, September, and December.
Common use cases:
- Gardening and planting season planning
- Travel and vacation timing
- Seasonal business planning
- Educational astronomy reference
Frequently Asked Questions
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