These flavors are only available during these months:

January: Egg Nog & Peppermint
February: Cinnamon
March: Irish De Menthe
April: Crunchy Peanut Butter
May/June: Crunchy Peanut Butter
July/August: N/A
September: N/A
October: Dark Orange
November: Pumpkin Pie
December: Egg Nog & Peppermint