Calendar statistics

Build fixed Hebrew calendar reports for years 1–689,472: weekdays, year lengths, postponements, keviyos, molads and traditional mean seasons.

Choose an inclusive Hebrew year range and compare Rosh Hashanah weekdays, common and leap year lengths, Cheshvan and Kislev, postponements and the 19-year cycle. Reports count monthly traditional mean molads and Rav Adda and Shmuel seasonal calculations with exact integer arithmetic. Export the selected report tables as CSV.

This tool studies the mathematical fixed calendar. Traditional mean seasons and clock equivalents are distinct from observed astronomical seasons, local sunset and practical halachic decisions.

Jewish Cosmology is an interactive research and educational web application connecting Hebrew dates, traditional Jewish calendar calculations and halachic concepts of time with the observable motions of the Sun, Moon and planets, astronomical seasons and eclipses.

JavaScript is required for the interactive explorers and calculations. The descriptions and navigation remain available without JavaScript.