After experiencing a particularly dry start to June and several days of poor air quality, southern Ontario is set to receive some much-needed rain throughout most of Monday. 

Environment Canada issued a special weather statement for the City of Toronto early Monday morning, which warned of heavy rainfall amounts anywhere from 30 to 50 millimetres, with locally higher amounts possible. 

"Rain associated with a low pressure system will continue to push into the region early this morning and taper off this afternoon. Heaviest rainfall is expected later this morning," the weather statement reads. 

The weather agency did note that there remained some uncertainty with rainfall amounts and the exact track of the low, which may eventually require an upgrade to the rainfall warning. 

☔Significant Weather Outlook for tomorrow. 🌧️
🌧️30-50 mm of rain is possible for parts of southern and northeastern Ontario starting tonight and through Monday. #ONstorm #ONwx pic.twitter.com/jaYqKCfeUa

— ECCC Weather Ontario (@ECCCWeatherON) June 11, 2023

The Toronto and Region Conservation Authority (TRCA) also issued a watershed conditions statement, which warned that all TRCA rivers within the GTA may experience higher than normal flows and water levels. 

"The combination of slippery, unstable banks, and changing water levels could create hazardous conditions in and near rivers or other water bodies," the TRCA said. "All shorelines, rivers and streams within the GTA should be considered hazardous." 

The heavy downpour is expected to alleviate some of the region's smoky air, however, it may only have a limited effect considering how out-of-control some fires in Quebec still are.

Ontario's Air Quality Health Index for Toronto is expected to peak at 4 on Monday, which is a moderate risk. By Monday afternoon, air quality is expected to improve to level 3, which is considered low risk.