The Karaite Korner has several articles on Biblical Holidays and the Biblical Calendar:

Biblical Holidays Dates

Find out the dates of this year's Holidays according to the true Biblical Calendar, based on the Abib (ripening barley) and crescent New Moon.

New Moon in the Bible

Learn what the Hebrew Bible says about the New Moon.

Abib (Barley)

The Biblical Year begins with the first New Moon after the barley in Israel reaches the state in its development which the Bible calls "Abib" as in the verse "Keep the Month of the Abib" (Dt 16,1).

Abib - Frequently Asked Questions

Answers to frequently asked questions regarding the Biblical Calendar and how Abib is used in intercalation.

Passover Haggadah

The Torah commands us to tell over the story of Exodus on the first night of Passover. The Karaite Haggadah uses the Biblical narative to retell this story.

Shavuot (Feast of Weeks/ Pentecost)

Shavuot (Feast of Weeks/ Pentecost) is the Biblical harvest-festival celebrated 50 days after the Sunday which falls out during Passover. These fifty days are called the Counting of the Omer. The Rabbis incorrectly celebrate Shavuoth on the 6th of Sivan.

Yom Teruah ("Rosh Hashannah")

Yom Teruah is a holiday on the 1st day of the Seventh month (Tishrei). The Rabbis wrongly call it New Years (Rosh Hashannah) when really it is a Day of Shouting (Teruah) in prayer to God.

Yom Kippur

Yom Ha-Kipurim (Yom Kippur), the Day of Atonement, is a fast day on the Tenth Day of the Seventh Month (Tishrei).

Sukkot (Feast of Booths)

On Sukkot (Succos/ Tabernacles) we are commanded to build a Sukkah (Booths) using as building materials the "4 species" listed in Lev 23,40, which the Rabbanites claim are to be carried as a bundle.