Freeze Risk by Crop Stage

Select crop and phenological stage, enter an observed or forecast temperature, and compare it with published critical-temperature reference values. This tool does not predict frost occurrence or field-specific injury.

Updated 2026-07-16

Reviewed by Daniel Dick · 2026-07-16

Calculator

Enter your values and click Calculate.

What this calculator determines

How an entered temperature compares to published T10 and T90 critical-temperature references for a selected crop and bud or bloom stage.

Formula or calculation method

The calculator looks up T10 (about 10% kill) and T90 (about 90% kill) from the embedded reference table for the selected crop and stage.

margin to T10 = entered temperature − T10

margin to T90 = entered temperature − T90

Plain-language read:

  • Above T10 — limited injury risk under table assumptions
  • Between T10 and T90 — partial injury risk is possible
  • At or below T90 — severe injury risk under table assumptions

Definitions of inputs

  • Crop — Apple, pear, peach, plum, or cherry (per available table entries).
  • Phenological stage — Bud or bloom stage matching current orchard conditions.
  • Forecast / observed temperature — Temperature you want to compare, in °F.

Worked example

Example only — not a recommendation.

Apple at tight cluster, forecast 26 °F, table T10 = 28 °F and T90 = 22 °F:

  • Margin to T10 = 26 − 28 = −2 °F (below T10)
  • Margin to T90 = 26 − 22 = +4 °F (above T90)
  • Read: between T10 and T90 — partial injury risk is possible

How to interpret the result

Use the comparison as background when deciding how closely to monitor temperatures. It does not forecast frost, estimate site-specific injury, or recommend protection measures. Confirm with current forecasts and on-site readings.

References

Critical temperature values are stored in the calculator’s frost-thresholds data table and displayed as published references for each crop and stage.

Assumptions

  • Critical temperatures are published general references, not site-specific guarantees.
  • Stage selection matches the crop's current phenology as closely as possible.

Limitations

  • Does not predict whether frost will occur.
  • Does not estimate field-specific injury probability.
  • Does not recommend protection equipment or actions.

Version 0.1.0 · Last updated: 2026-07-16 · Reviewed: 2026-07-16

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Disclaimer

This tool compares your inputs to static thresholds. Local site conditions, radiation, wind, and exposure duration can change actual outcomes.