tmp_min_ave

This value is calculated by summing the minimum air temperature for every day in the month for all years of record and dividing the sum by the number of days:

where $μmn_{mon}$is the mean daily minimum temperature for the month $mon$ (ºC), $T_{mn,mon}$ is the daily minimum temperature on day $d$ in month $mon$ (ºC), and $N$is the total number of daily minimum temperature records for month $mon$.