““Since the dates are referenced to Noah’s age, it makes the most sense that Moses kept the dating system that was utilized on the ark while penning Genesis 7–8. Keep in mind that the later Israelite calendar (i.e., the Babylonian calendar) was lunar.12 The months alternated with 29 or 30 days. In the Bible, we find that 150 days was equivalent to 5 months based on the context in the Flood account (Genesis 7:24–8:413). This would yield month-lengths of 30 days each, not 29 and 30 days alternating for 5 months (as in a lunar calendar).””
