Environment Canada issued a severe thunderstorm warning and watch for August 6.
Conditions were favourable for heavy rain, and winds of up to 90 kilometres per hour were possible.
Hail, thunder and lightning were also possibilities.
A thunderstorm watch was in effect as of 11:45 a.m. for the following areas:
- Guelph - Erin - Southern Wellington County
- Kitchener - Cambridge - Region of Waterloo
- Mount Forest - Arthur - Northern Wellington County
The watch was upgraded to a warning in Kitchener - Cambridge - Region of Waterloo just after 1:00 p.m.
According to Environment Canada's website, locations impacted also include Lucan, St. Marys, Stratford, Tavistock, Wellesley and New Hamburg.
Officials advise people to stay indoors during severe weather, and to plan travel accordingly.
'When thunder roars, go indoors.'
