Generally..
Around Dec, Jan Feb. Is best for hiring.
People who know they didn't perform great or their company generally is not generous/entitled to PB, people rather jump ship early if they know the next company sure pays good PB/AWS

March April. Government is forced to hire.
Financial year ended, PB paid. The job is good but people seek a jump in salary so they leave for better positions rather than wait to be recognized.

May, June. Leftover jobs generally not attractive package, or people give up due to work mismatch.

People don't resign after August because a final quarter can take bonus already, plus if vacancies appear often people are so pissed off with the politics that they rather be jobless. So any opening after June.. Generally is less than ideal.

Hiring can generally take place anytime, this is a rather traditional perspective.