KITCHENER -- Line ups began even before spray parks even opened on Thursday morning.

Families descended onto splash pads to cool off as a heat wave settled over southwestern Ontario. Some facilities are still closed due to the COVID-19 pandemic. And, the ones that are open, are enforcing physical distancing.

"The old ones like the buckets and the dumps, the younger ones just like the ones that squirt, so it just has something for everybody," said Leisha Nabrotzky, who brought her three daughters to the spray park.

By mid-afternoon on Wednesday, Environment Canada had issued a heat warning for much of southern Ontario. Humidex values will likely hit 40C and the environmental agency is warning of dizziness/fainting; nausea/vomiting; rapid breathing and heartbeat and extreme thirst. The risks are greater for young children, pregnant women, older adults, people with chronic illnesses, the agency noted.

Local outdoor water facilities are operating at a reduced capacity and staff are monitoring the area.

Spray pads are just one option for people battling the hot weather. Other suggestions for staying cool include sprinklers and ice cream.