Hebrew Calendar Months 

English   # Length Gregorian
Nissan   1 30 days March-April
Iyar   2 29 days April-May
Sivan   3 30 days May-June
Tammuz     4 29 days June-July
Av   5 30 days July-August
Elul   6 29 days Aug-Sept
Tishri   7 30 days Sept-Oct
Chesvan   8 29 or 30 Oct-Nov
Kislev   9 30 or 29 Nov-Dec
Tevet 10  29 days Dec-Jan
Shevat 11 30 days Jan-Feb
Adar I *
(leap years only)
12 30 days Feb-March
Adar
 
12 29 days Feb-March