The Gregorian Calendar is solar and the Hebrew Calendar is lunisolar.
In the Hebrew calendar, the month of Av is followed by the month of Elul.
1 week = 1 week on the Hebrew calendar. (The Hebrew week is the same length as the week on the Western calendar)
There isn't any festival celebrated along with Christmas as per the Hebrew calendar, since Christmas is not tied to the Hebrew calendar. (So every year, Christmas falls on a different date on the Hebrew calendar).
The Hebrew calendar is used in Israel, and by Jews all over the world.
A Hebrew calendar website can help you with that.
In the Hebrew calendar, the month of Nissan immediately precedes Iyar.
The Hebrew month Adar is the same in all countries. It is a Spring month.
The tenth month in the Hebrew calendar is called "Tamuz". It usaually falls out around July time.
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.
Hebrew Calendar.
check out this graphical calendar example below