No - a number of hourly paid people will receive their actual money monthly. The two aren't necessarily connected.
However there may be administrative or contractual reasons why the employer prefers to pay hourly paid people weekly.
Some people however refer to "Monthly pay" as shorthand for a salaried/fixed amount - the two aren't connected. You can be paid a fixed amount weekly or monthly or a variable amount based on hours worked weekly or monthly (or 4 weekly or fortnightly or almost anything else). Its largely down to contract.
Many employers have moved towards monthly pay for their own convenience over the past 20-30 years.