A week of very high temperatures and humidex advisories has helped set new peak power usage records for the year at power utilities in Waterloo Region and Wellington County.

Guelph Hydro said it expects to break its all-time usage record for the second day in a row on Wednesday.

Peak usage on Wednesday at 1:30 p.m. was 302.1 megawatts, up from the record set Tuesday of 297 megawatts, according to Guelph Hydro spokesperson Sandy Manners.

As people retreated to their homes to wait out the warm weather Monday and Tuesday, the drain on the power grid was the heaviest Kitchener-Wilmot Hydro has seen all year.

Kitchener-Wilmot Hydro says Tuesday night at 6:15 p.m. peak use hit 372 megawatts, following a peak of 371 megawatts the day before.

Cambridge and North Dumfries Hydro reports peak usage on Tuesday was 300 megawatts, topping this year's records.

Environment Canada issued a humidex advisory for Waterloo Region and surrounding area Wednesday. Temperatures are expected to hit 33 — but feel like low-40s.

With files from the CBC's Mike McCulloch