It’s the first day of the summer that pools are open across New York City, but the launch isn’t going as smoothly as it could.

A nationwide lifeguard shortage is hitting New York hard. That shortage is creating challenges for the city’s Parks Department, which says operation at some pools may have to adjust based on daily lifeguard count.

Commissioner Sue Donoghue says some pools may have to operate at reduced capacity, and others may even have to be closed for a day.

This year, the department says there are 660 lifeguards, but its goal is to have between 1,400-1,500.

The lifeguard shortage has forced the city to cancel all swim programs, including swimming lessons for kids and adults.

If there is no lifeguard at the pool, make sure to not swim alone, and avoid swimming in water that is too deep.

Pools will be open at 11 a.m.-7 p.m. daily, but there’s a break from 3 p.m.-4 p.m. for pool cleaning. City pools are expected to stay open until Labor Day weekend.

MORE: Ready to make a splash this summer? Here are 10 water safety tips