Understanding the difference between weather watches and warnings 

A bolt of lightning appears in the sky over Sperling, Man. on June 7, 2025. (Ken Russell)

As Manitoba contends with wildfire smoke, thunderstorms and potential tornadoes, residents are inundated with weather watches and warnings.

Though most people know these watches and warnings mean to prepare for extreme weather conditions, they may not know the difference between the different types of alerts.

According to Environment and Climate Change Canada (ECCC), a watch is issued when conditions are favourable for the development of a certain weather event, like a tornado or tropical storm. A warning is issued when the weather event is expected or reported.

For example, a tornado watch is declared when conditions are favourable for the development of a severe thunderstorm with one or more tornadoes, while a warning is issued when there is evidence that a tornado is imminent.

While some watches and warnings must meet national criteria to be sent out, others have to meet a regional threshold. For example, while the threshold criteria for severe thunderstorms are the same across the country, they are not for extreme cold warnings.

More specifically, an extreme cold warning is issued in southwestern Ontario when the temperature or wind chill is expected to reach -30 for at least two hours, while in southern Manitoba it’s only issued when it’s expected to drop to -40 and in northern Manitoba -45.

ECCC adds that a generic weather advisory or warning is issued for extreme weather events for which there is no suitable warning type, while air quality warnings are based on the severity of the air quality health index.

More information on all the specific criteria is available online.