Freezing Index Calculator

Formula

To calculate the Freezing Index (\(FI\)):

\[ FI = \sum \frac{(T_f - T_a)}{n} \]

Where:

\(FI\) is the Freezing Index (°C-days)
\(T_f\) is the freezing temperature, typically 0°C
\(T_a\) is the average daily air temperature (°C)
\(n\) is the total number of days in the period being considered

What is a Freezing Index?

A Freezing Index is a meteorological term that refers to the cumulative effect of freezing temperatures over a certain period, typically a winter season. It is calculated by adding up all the degrees of the average daily temperature below freezing (0°C or 32°F). This index is used in various fields such as civil engineering to estimate the depth of frost penetration into the ground or to assess the severity of winter conditions in different regions.

Example Calculation 1

Let's assume the following values:

Average Daily Air Temperature (\(T_a\)) = -5°C
Number of Days (\(n\)) = 30

Using the formula:

\[ FI = \sum \frac{(0 - (-5))}{30} = \sum \frac{5}{30} = 0.17 \text{ °C-days} \]

The Freezing Index is 0.17 °C-days.

Example Calculation 2

Let's assume the following values:

Average Daily Air Temperature (\(T_a\)) = -10°C
Number of Days (\(n\)) = 60

Using the formula:

\[ FI = \sum \frac{(0 - (-10))}{60} = \sum \frac{10}{60} = 0.17 \text{ °C-days} \]

The Freezing Index is 0.17 °C-days.