Below, you can see some coding:
January = 1017
February = 628
March = 1335
April = 145
May = 1353
June = 1064
July = 1074
August = 186

Now deciphering the way it has been coded, can you find out how September will be coded?

January = 10|1|7
10 is the position of letter J in alphabetical order.
1 is the position of January in months.
7 is the number of letters used in the word January.

Same goes for all the months, thus
September = 19|9|9 (1999).