Rosh Chodesh Adarרֹאשׁ חוֹדֶשׁ אֲדָר

Rosh Chodesh Adar is the new moon that opens Adar, the month of Purim. It is always kept for two days, the 30th of Shevat and the 1st of Adar. On a weekday the Torah reading is Numbers 28:1-15, the offerings for the new month, in four aliyot. Half-Hallel and Mussaf are added to the prayers on both days. When Rosh Chodesh Adar falls on Shabbat it is also Shabbat Shekalim (in a leap year, only Rosh Chodesh Adar II), and the Torah is read from three scrolls: the weekly portion, the Rosh Chodesh passage, and the Shekalim maftir. In a leap year Adar is doubled into Adar I and Adar II, each with its own two-day Rosh Chodesh, and Purim and Shabbat Shekalim belong to Adar II. Rosh Chodesh Adar carries a distinct emotional charge: it opens the month that holds Purim, and tradition treats the very start of Adar as the moment to begin lifting one's spirits. The Talmud's dictum "Mishenichnas Adar marbim b'simcha" ("When Adar enters, we increase in joy," Ta'anit 29a) frames the whole month, and Rashi connects that joy to the Purim deliverance and the approaching season of redemption at Pesach. Like every Rosh Chodesh, it is a minor festival rather than a work-prohibited holiday, historically linked to the renewal of the moon as a recurring symbol of national renewal. In a Jewish leap year the month is doubled into Adar I and Adar II, so the "head of Adar" is observed twice; by the common reckoning the heightened joy and Purim itself attach to Adar II, though customs on which Adar carries the full weight of "increasing joy" vary.

Rosh Chodesh Adar falls on the 1st of Adar and is observed for two days, because the preceding month of Shevat always has 30 days: the 30th of Shevat counts as the first day of Rosh Chodesh and the 1st of Adar as the second. On the civil calendar this usually lands in February, with the exact dates shifting each year. In a Jewish leap year (7 years out of every 19) the month is doubled, producing two separate observances, Rosh Chodesh Adar I and Rosh Chodesh Adar II, each likewise two days long, with Purim kept in Adar II. The date, length, readings, and liturgy of Rosh Chodesh are the same in Israel and the Diaspora; unlike the pilgrimage festivals, Rosh Chodesh has no extra Diaspora day, and its two-day length here comes only from Shevat having 30 days, not from any Israel/Diaspora distinction. Minor wording differences between Ashkenazi and Sephardic rites exist in the prayers but do not change when it is observed.

On a weekday Rosh Chodesh Adar the Torah reading is Numbers (Bamidbar) 28:1-15, the passage describing the additional Rosh Chodesh Temple offerings, divided into four aliyot, with no Haftarah. When Rosh Chodesh Adar falls on Shabbat, that Shabbat is also Shabbat Shekalim, and the Torah is read from three scrolls: the weekly parashah in six aliyot from the first, Numbers 28:9-15 as the seventh aliyah from the second, and the Shekalim maftir, Exodus 30:11-16, from the third. The Haftarah is Shabbat Shekalim's (II Kings 12:1-17 for Ashkenazim, II Kings 11:17-12:17 for Sephardim), and many Ashkenazim add the first and last verses of the Rosh Chodesh Haftarah, Isaiah 66:1 and 66:23. The exception is Rosh Chodesh Adar I in a leap year, which is not Shabbat Shekalim: the weekly parashah is read in seven aliyot, Numbers 28:9-15 as maftir from a second scroll, and the Haftarah is the regular Shabbat Rosh Chodesh Haftarah, Isaiah 66:1-24 ("Ha-shamayim kis'i," "The heavens are My throne"), chosen because Isaiah 66:23 names both Rosh Chodesh and Shabbat. Notably, Rosh Chodesh has no unique cantillation melody of its own: the Torah portion is chanted in the standard everyday Torah trope and the Haftarah in the ordinary Haftarah trope, unlike the distinctive melodies of Eicha, the Megillah, or the High Holidays. (The aliyah breaks vary slightly between rites; a common division is 28:1-3, 3-5, 6-10, and 11-15.)

The Rosh Chodesh morning service adds Half-Hallel (Psalms 113-118 with the opening of 115 and 116 abbreviated) and a Mussaf (additional) Amidah recalling the Rosh Chodesh offerings, and the Ya'aleh V'Yavo paragraph is inserted into the Amidah and into Birkat Hamazon throughout the day. On the Shabbat before Rosh Chodesh (Shabbat Mevarchim), the congregation announces and blesses the coming month with Birkat HaChodesh after the Torah reading. A traditional custom holds that women refrain from certain work on Rosh Chodesh, understood in Midrash as a reward for the women who declined to give their jewelry for the Golden Calf; modern Rosh Chodesh women's groups build on this. Specific to Adar, communities embrace "Mishenichnas Adar marbim b'simcha," increasing joy from the month's start, and the surrounding Shabbatot carry special readings: Shabbat Shekalim on or just before Rosh Chodesh Adar (or Adar II) and Shabbat Zachor before Purim. Liturgical details such as the precise Hallel and Mussaf wording differ somewhat between Ashkenazi and Sephardic rites.