Hebrew Calendar

	Hebrew	Academy	Length	Holiday / Notable days	Notes
1	נִיסָן	Nisan	30 days	Passover	Called Abib ( Exo 13:4, 23:15, 34:18, Deu 16:1 ), and Nisan ( Est 3:7 ) in the Tanakh.  1st Nissan = ecclesiastical new year for counting of months and festivals.
2	אִיָּר / אייר	Iyyar	29 days	Pesach Sheni, Lag B'Omer	Called Ziv in 1Kings 6:1, 6:37
3	סִיוָן / סיוון	Siwan	30 days	Shavuot
4	תַּמּוּז	Tammuz	29 days	Seventeenth of Tammuz	Named for the babylonian god Dumuzi
5	אָב	Av	30 days	Tisha B'Av, Tu B'Av
6	אֱלוּל	Elul	29 days		New Year for tithing animals
7	תִּשׁרִי	Eishri	30 days	Rosh Hasahnah, Yom Kippur, Sukkot, Shimini Atzeret, Simchat Torah	Called Ethanim in 1Kings 8:2.  1st Tishrei = civil new year, .
8	מַרְחֶשְׁוָן / מרחשוון	Marheshwan	29 or 30days		Called Bul in 1Kings 6:38
9	כִּסְלֵו	Kislew	30 or 29 days	Hanukkah
10	טֵבֵת	Tebeth	29 days	Tenth of Tevet
11	שְׁבָט	Shevat	30 days	Tu Bishvat	New Year for trees and agricultural tithes
12 #	אֲדָר א׳	Adar I	30 days		only in Leap years
12	אֲדָר /  אֲדָר ב׳	Adar / Adar II	29 days	Purim