In a city known for being cold, a Toronto man did a really cool deed for a needy lady on a sweltering day.

Helen Banville, 77, had been caught on her porch by CTV Toronto's cameras at noon on Thursday. She said the 33-degree-Celsius weather outside -- 43C with the humidity factored in -- was cooler than the inside of her bungalow.

The temperature inside the home reached 36 C.

"Terrible hot, terrible hot," said the survivor of two open-heart surgeries.

Joseph Samardzich saw Helen suffering in the heat and decided to help. He bought her an air-conditioning unit, installed it and told her he would come back and uninstall it in the fall.

"I got … some tools, some wood, some tape, extension cord -- everything she needs to keep cool," he said. "By 5 p.m. this afternoon, she'll be needing a sweater."

The gesture warmed Helen's heart.

"I'm the luckiest person in the world," she exclaimed. "I've never had a thing ever given to me."

They hugged, and then Samardzich got to work.

"It restores your faith in humanity," said Teresa Pulfer, Helen's neighbour. "It makes you feel like there's a lot of good people out there."

After the cool air started flowing, Helen chuckled and said, "I'll be able to sleep like a baby tonight."

She was lucky. CTV Toronto found one big-box retail store to be sold out of air conditioners and fans.

Grumpy TTC riders

Unfortunately, there was no air conditioning on TTC streetcars Thursday. Some riders were wondering if the operators were running the heating units by mistake.

But the TTC did say its ventilation system was circulating very hot air.

The temperature inside was about 36 C with the humidity. Passengers said it was unbearable.

Air-conditioned streetcars will become available starting in 2013.

Meanwhile, a construction worker collapsed downtown. Paramedics came to help him out, and they said this type of call during has been quite common during the four-day heat wave.

"If they're exerting themselves outdoors, anywhere within 15 to 30 minutes, they can start feeling the onset of heat-related fatigue," said Wade Lansing of Toronto EMS.

From there, a person can progress quite quickly to unresponsiveness, he said.

CTV Toronto's Austin Delaney noted that the city should get about 15 days above 30 C this summer. Last summer, there were only three.

Since summer began, Toronto has experienced nine days above 30C, he said.

Weather changing

Environment Canada had severe thunderstorm watches for much of central and southwest Ontario for Thursday afternoon. By about 8 p.m., it started lifting those warnings as the threat moved into eastern Ontario for the evening.

There was no severe weather warning for the GTA. However, the area can expect a 30 per cent chance of showers Thursday evening. There is an 80 per cent chance of showers Friday morning, said CTV Toronto weather anchor Tom Brown.

He noted there were heavy showers in Windsor and some near Georgian Bay.

Friday will also see a temporary end to the heat, which peaked at 33 C Thursday, with the humidex reading reaching at 43 C. Friday's predicted high is 24 C.

Weekend temperatures are predicted to be in the high 20s.

Smog lifting

Smog advisories were lifted in some areas of southern Ontario.

The Ministry of the Environment says advisories are no longer in effect for the Barrie-Orillia-Midland, Grey-Bruce, Haliburton and the Parry Sound-Muskoka-Huntsville regions.

The ministry says it lifted the advisories because increasing cloudiness, ahead of the approaching cold front, is leading to cleaner air in those regions.

However, smog advisories remained in effect for most other areas of southern Ontario.

With reports from CTV Toronto's Austin Delaney and Janice Golding