Use this phrase when you're talking about things that usually happen during a certain season. It can be used when talking about weather, business, holidays, and other topics. For example:

The stores are always packed at that time of year.

It tends to rain a lot at this time of year.

Notice that the phrase is "that time of year", not "a year" or "the year".

it's (comparative adjective) (somewhere) than it is (somewhere)

Use this phrase to compare descriptions of two places. Some more examples:

It's less crowded there than it is in New York.

It's noisier in Calcutta than it is in Singapore.