In the Hebrew calendar, the month of Av is followed by the month of Elul.
The Hebrew month Adar is the same in all countries. It is a Spring month.
Nisan is the 7th month in the Hebrew calendar. The word comes from Babylonian, and has an unknown meaning.
April is not a month in the Hebrew calendar, and the Sundays in any Hebrew month could easily change from year to year, just as they often do for any month in the civil calendar.
The name of the Hebrew month that comes before Iyar is called: "nisan".
The tenth month in the Hebrew calendar is called "Tamuz". It usaually falls out around July time.
Adar.
tevet
There are 12 months in the Hebrew calendar. In a leap year there are Adar A and Adar B. Adar is the sixth month.
Cheshvan
It's a month in the Hebrew calendar, also spelled Lyar, which comes after Nisan and before Sivan. The festivals of Pesach Sheni and Lag B'Omer take place during Lyar.
Av is the 5th Month of the year on the Hebrew calendar. It usually occurs in June or July