Heidegger's Bible Handbook: Numbers: The Chronology of Numbers
4. The chronology of the book.
* Disclaimer: I do not vouch for everything in this chart.
Moreover, this book covers the history of thirty-nine years. For the beginning of the matters that are narrated as conducted in it falls upon the first day of the second month of the second year of the Exodus, as it is expressly written in Numbers 1:1. But the matters conducted in it are extended unto the first day of the eleventh month of the fortieth year after the Exodus, as it is gathered out of Deuteronomy 1:3. Therefore, it is an interval of thirty-nine years, with only two months less.