People in southern Saskatchewan with breathing problems are being asked to be careful on Thursday.

Smoke from northern Saskatchewan forest fires is continuing to affect areas to the south and southwest.

Meanwhile, smoke from southern Alberta will also spread into southern Saskatchewan through the morning, covering Moose Jaw, Swift Current, the Battlefords and Saskatoon. Hazy skies and even reduced visibility is possible.

Anyone with lung problems, children and seniors are especially at risk.

Anyone at risk is asked to stay inside with the doors and windows closed.

Southerly winds are expected to push the smoke in the south towards northern Saskatchewan tonight.

Heat warning

Meanwhile, the province's southwest is under a heat warning.

Swift Current, Gull Lake and Piapot can all expect temperatures above 30 C today.

Environment Canada says a low pressure system will be spreading heat out of the United States. An incoming cold front this afternoon should return temperatures to normal by tonight.

People may experience swelling, heat stroke and fainting.

People are asked to schedule outdoor activities for cooler parts of the day, and to never leave people or pets inside a parked vehicle.