Hochul announced at a press conference Friday that masks must be worn indoors when people go out in public unless the business requires customers to be vaccinated.
The guideline takes effect on Monday and runs through Jan. 15, at which point the state says it will reevaluate.
The state recorded nearly 70,000 positive tests over the past week -- that's the most in any seven-day stretch since the start of February.
Hochul says those who don't follow the mandate could face civil and criminal penalties, including a fine of up to $1,000.
The city says in the past week there was a daily average of more than 2,300 New Yorkers who tested positive for the virus. By comparison, the city says the daily average over the last month was just 1,700.
The trend shows cases are increasing in the city.