More on the Frogs
The Mishna in Eiduyot 2:10 says that the Makkot lasted 12 months. The Tosefot Yom Tov there quotes the Seder Olam Rabba (chapter 3) that implies that the Makkot started in Iyyar and ended in Nissan. The Tiferet Yisrael there says that each Makka was a little more than a month long.
Let's see: The oil rig blew up on April 20th, which was the 6th of Iyyar. The frogs started closing the highway on May 26th, which was the 13th of Sivan. We start to see the 1 month and 1 week interval.
|Nissan 9||Makat Bechorot|
Only off by 6 days. Hmmm...