Q: #219. How long did the 10 plagues of Egypt last?
By: Steve Shirley
A: The Bible does not tell us the answer to this question, and as a result, there are numerous guesses. These range anywhere from about a month to about a year (the Jewish Mishnah says 1 year). Based on my studies, I am guessing about 4-5 months. Here is why.
We do know several facts for sure. First, the Bible says in (Ex 7:6) that Moses was 80 years old when the 10 plagues started after he spoke to Pharaoh. After the plagues were done, and Pharaoh finally let the Israelites go, they wandered in the desert for 40 years (Num 14:33-34, 32:13). Moses died at the end of the 40 years at the age of 120 (Deut 34:7). Therefore, if Moses was 80 at the start, wandered 40 years, and died at 120, the plagues had to have ended in under a year.
I believe we can narrow this time down even more by looking at a few other facts. We know the duration of 3 of the plagues. The first plague lasted for 7 days (Ex 7:25), the 9th lasted for 3 days (Ex 10:21-23), and the 10th was for one night, beginning at midnight (Ex 12:29-31).
While we don't know the length of the other 7 plagues, it is my guess that none of them were much longer than these. I don't think they could have withstood them, except for a very short period of time. For example, I read somewhere that it would only take a few days for a swarm of millions of locusts (the 8th plague) to destroy every bit of green vegetation in sight. This being said, if we make the average length of each plague say 4 days, we have a total of 40 days that the plagues lasted. This is also a Biblical number that corresponds with the lengths of other punishments i.e. 40 years of wandering in the desert (Num 14:33-34, 32:13), 40 days of rain for Noah's flood (Gen 7:4,12), Goliath tormented Israel for 40 days before God helped David kill him (1 Sam 17:16), God gave Nineveh 40 days to repent or be destroyed (Jonah 3:4).
The biggest problem we have is not knowing the length of time between the different plagues. My feeling is that it was not a lot of time. A few other facts can help us in making this determination. I believe that the timeframe between the 7th plague (hail) and the 10th plague (death of the firstborn) was no more than a few months. I say this because (Ex 9:31) says that when the hail came, all of "the flax and barley were ruined, for the barley was in the ear and the flax was in bud." (Ex 9:32) "But the wheat and the spelt were not ruined, for they ripen late." We know that "flax and barley" are in bloom in February, with wheat and spelt being in bloom a month or two later. Also, when the 8th plague was sent (swarms of locusts), God said they would destroy "every plant of the land that the hail left." (Ex 10:12). This means that it shortly followed the hail, still before the wheat and spelt were in bloom (probably in late February or early March).
We also know that the last plague fell either in late March or early April, because that is the time of the Jewish Passover, when God passed over the houses of the Israelites and did not kill their firstborn because they had the blood of the Passover Lamb covering the doorframes of their houses (Ex 12:21-27).
Therefore, the timeframe for the 7th plague through the 10th plague was almost certainly no more than a month and a half to two months. This works out to about 2 weeks at most for each (the length of the plague plus the warning proceeding it). If we carry this out to the other 6 plagues, we get 12 weeks. So, the total is 20 weeks or about 4 to 5 months for all 10 plagues.