Several southern Ontario communities saw more rain on Sunday and braced for still more wet weather a day after a storm soaked the region and broke at least one precipitation record.

Heavy rainfall warnings from Environment Canada remained in effect for a region that includes the Greater Toronto Area, with more than 100 millimetres of precipitation expected in some places.

In Toronto, the agency said the ground has little ability to absorb further rainfall after torrential downpours drenched the city on Saturday. Another 15 to 30 millimetres was forecast for Sunday evening.

Saturday's downpour dumped 128.3 millimetres of rain at Toronto Pearson Airport. That topped the 2013 record of 126 millimetres recorded at the airport, which is on tap for its rainiest summer ever.

"It's fair to say that this has been a record-breaking season," said Environment Canada meteorologist Trudy Kidd.

Kidd said seasonal data isn't always complete, but available numbers already make the outcome clear.

The previous record for summer rainfall stood at 396.2 millimetres, but Kidd said the airport has already seen 475.7 millimetres this season.

The weekend rain in the region is part of a larger storm system that wreaked havoc in southern Ontario on Saturday.

The rain triggered numerous road closures in the Toronto area and stranded several vehicles in deep water, Toronto police said.

Toronto Pearson Airport said airlines are still recovering from Saturday's storms, flights delayed and terminals bustling with carry over passengers from the day before. The Greater Toronto Airports Authority urged anyone with Sunday travel plans to check their flight status before leaving home.

The city of Mississauga saw localized flooding due to the rain on Saturday, with the weather disrupting traffic and causing the closure of some local parks and trails. As of Sunday morning, the city said on its website that most of the flooding had receded, but noted a rainfall warning was still in place.

Rain wasn't the only extreme weather to hit the region. A tornado touched down Saturday morning in the community of Ayr, Ont., about 115 kilometres southwest of Toronto.

Western University's Northern Tornadoes Project confirmed the twister touched down around 11 a.m., bringing with it winds that reached 165 km/h.

The project's executive director, David Sills, said his teams are still assessing the size of the storm.

"We've got trees down in every direction possible," Sills said, but noted "this one was on the weak side."