Can you explain a Hebrew Calender & it's similarities & differences with Islamic, Christian, & Pagan Calendars

Question

I am especially interested in the dating and actual timing of religious holy days.

I wish to add, "with the seasons."

Answer 1

it's funny, i was just reading up on it because a rabbi was saying something weird about the months and there you came with the question.

the hebrew calendar is based on the acadian, babilonian sumerian calendar.
it's a lunar calendar which is adjusted to the length of the solar year throught the addition of 7 extra "adar" months every 19 years (the calendar "zeros" every 96 years).

the months are mostly derived from ancient messopotamean gods and agricultural activities.

(the moslem calendar is lunar, but with no adjustment, so it moves about 10 days every year).

the holidays are adjusted to different agricultural (and therefore natural) events:

on tishri, the month of beginning there are the beginning of the year, the day of atonement and succoth, the feast of gathering, gathering your stuff from the field before the first rains.
hannuka (added only after 160 bce) is a festival of light (falls around december) probably related to mid winter.
tu bishvat "new year for the plants"... some plants, such as the almond begin to bloom, the beginning of renewal.

purim ... pre spring (connected to carnivals and dressing up and gettnig drunk... and of course godly salvation) is the time when you dont know yet how the year will be, will the rains suffice, is spring gonna start on time?

pessah (passover) spring is starting (full moon of april). things begin to grow.

then 7 weeks of pentacost waiting for the first harvest... (with a festival of fire 35 days after passover (added around 135 ce) and then pentacost, first harvest, bring first offering to the temple.
tu be-av "festival of love", of summer, of pressing the wine and of courtship.

then... elul the month of harvesting the wheat... then we start all over again.