Degree Day Calculator For Blandy Experimental Farm Weather Data

Dates Covered in weather database: Feb 01, 1984 to Jul 31, 2018

Min Degree (Celsius) To Use as Activation Temperature
Calculate degree days (celsius) for each year until this date (format mm-dd as in 05-11)
Find first date of each year to reach this total of degree days (integer value)



What can you do with this?
You can calculate for every year in the database the total amount of degree days accumulated to a specified date or you can calculate the first date of each year for which a degree day amount was reached. If you know the degree day formula for an event then you can estimate the day each year that it occurred. The data come from daily manual observations at a weather station

What is a degree day calculator?
Many species of plants and animals go into dormancy in winter and require a certain amount of warming to occur after winter before they become active. The amount of warming is calculated as degree days, an accumulation of heat exposure above a threshold activation temperature. The activation temperature varies for different organisms and ideally would be measured experimentally, along with the total degree days required at that temperature. Lacking that information, a degree day model can be developed through trial and error with enough information regarding when particular events occurred and then tested in the future for its predictive power.

How does this calculator calculate degree days?
For each day it subtracts the activation temperature from the average of the max and min temperature. If that value is less than zero then it is recorded as zero --no heat accumulation. Thus, the higher the daily average temperature and the lower the activation temperature, the faster degree days accumulate. When a value is missing in the dataset, it is considered to be the same value as the day before.