Summing parts of a column

I have 18 years of daily weather temperatures. I want to sum the temperatures for a specific part of the each year. How could I find the temperature sum for 1st September to 31st November for each year so I end up with a 2 by 18 table that shows the year in the first column and the summed temperature for 1st September to 31st November corresponding to each year in the second column.

Sample data attached.

Much appreciated, Wendy

Answer 1

[KSSV]

YOu have multiple ways to do this.....

1. Create the time stamps you want...find the respective indices using ismemebr and do the sum.
2. Split the tdate vectors you have into respective months, years and pcik what you want and do the sum.