Growing Season Calculator
Count usable dates between entered frost boundaries and compare a crop's maturity range. See whether all, part or none of the range fits the season.
Starts with an editable example. Replace the dates and rules with your own.
Your calculation
Ready when you are
Choose your dates.
Select your counting rules and calculate.
Calculation details
| Step | Value |
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How to use this calculator
Enter the last frost before the growing season and first frost after it, using the correct calendar years. Add the minimum and maximum maturity days you want to compare.
Both frost boundary dates are excluded. Crop maturity is added after the first usable planting date, treated as day zero. These boundaries are entered estimates; no geographic climate records or weather forecast are loaded.
A worked example
Between May 1 and October 1, 2027 there are 152 strictly intervening dates, May 2 through September 30. There are 151 elapsed days from the first planting date to the last usable date.
Can I plan a season that crosses New Year?
Yes. Enter the actual years so the next frost follows the previous one. The boundary span is limited to 731 days.
Which calendar and years are supported?
Use Gregorian dates from 1900 through 2100, with results in that range. Daily attendance, office, coverage and chore plans allow up to 366 dates; school cycles, course plans and milestones allow up to 731. Dependency and historical workday calculations scan at most 3,661 dates. Class-session searches allow 366 dates and 200 sessions. Time-zone tools use browser IANA rules and require a choice when local times repeat. Dates and policy rules are entered manually; no employer, retailer, school or local weather policy is inferred. Copy, CSV and printing include the calculation rules; calendar exports appear when the result contains dated events.
What happens to my dates?
Calculations run on your device. Saving a calculation is optional and keeps it in this browser. A setup link contains the dates and settings you entered; anyone with the link can read them. Use one tab per saved calculator. Clear saved data from Privacy & settings.