Also x 2: During the first, second, fourth, and fifth years
of the seven - year
cycle, they took the tithes (food & drink) to a
particular location and had a massive party!
They're usable because they ARE accurate records
of the «conditions» at the time — crop
cycles and yields, rain, heat, cold, snow, ice pack, death records (both animal and human) and a lot more — and they give pretty accurate knowledge about what was happening and the general temp range at that
particular time and
location.