The following Matlab project contains the source code and Matlab examples used for positive degree day for normally distributed temperatures.
PDD fraction in a normally distributed climate
Calculates the probability weighted positive degree days for normally distributed temperatures:
T_june = 3; %degC
sigma_june = 7; %degC =std(daily_average_temps_june)
PDD_june=30*normalpdd(T_june,sigma_june) % units: degC*days