Weather tools

Chilling Hours Calculator

Calculates the accumulated chilling hours for a specified period, which is the number of hours below a critical temperature required by some plants to break dormancy and flower properly.

Before you use this tool

Use this if

  • Calculates the accumulated chilling hours for a specified period, which is the number of hours below a critical temperature required by some plants to break dormancy and flower properly.
  • You want a calculation that exposes its formula: Chilling Hours = Σ (Hours with Temperature ≤ Critical Temperature) (Summed over the specified period)
  • You already have Critical Temperature, Start Date, End Date values to enter.

Skip this if

  • You need an official emergency alert or life-safety instruction.
  • You need a certified professional forecast instead of a calculator estimate.
When to use or skip it

Use this if

  • Calculates the accumulated chilling hours for a specified period, which is the number of hours below a critical temperature required by some plants to break dormancy and flower properly.
  • You want a calculation that exposes its formula: Chilling Hours = Σ (Hours with Temperature ≤ Critical Temperature) (Summed over the specified period)
  • You already have Critical Temperature, Start Date, End Date values to enter.

Skip this if

  • You need an official emergency alert or life-safety instruction.
  • You need a certified professional forecast instead of a calculator estimate.