How to Read a Canadian Weather Forecast
Environment Canada's weather forecasts contain a lot of information. This guide explains every element — from probability of precipitation to wind chill values — so you can make informed decisions.
Understanding the Forecast Format
Environment Canada publishes weather forecasts in a consistent format across all regions of Canada. Once you understand the structure, you can quickly extract the information most relevant to your plans.
Step 1: Identify the Time Period
Canadian forecasts use a 24-hour clock and specify periods as "Today," "Tonight," "Tomorrow," and so on for up to 7 days. Each period covers roughly 12 hours. "Today" runs from the current time to approximately 6 PM local time. "Tonight" runs from 6 PM to approximately 6 AM the following day.
Step 2: Read the Temperature
Temperatures in Canadian official forecasts are always given in Celsius (°C). The forecast shows the expected high for daytime periods and the low for overnight periods. During winter, wind chill values are often included — this represents the "feels like" temperature accounting for wind speed. Wind chill below -25°C is considered dangerous for exposed skin.
Step 3: Understand Probability of Precipitation (POP)
When forecasts mention "Chance of rain 60 percent" or "POP 40%", this is the Probability of Precipitation. This means there is a 60% or 40% chance that measurable precipitation will occur at any given point in the forecast area. A POP of 70% or higher generally warrants carrying an umbrella or rain gear.
Step 4: Decode Wind Information
Wind forecasts show direction (where wind is coming FROM) and speed in km/h. A reading of "Southwest 30 gusting to 50" means winds blowing FROM the southwest at 30 km/h with gusts reaching 50 km/h. Sustained winds above 60 km/h are considered strong; gusts above 90 km/h cause damage.
Step 5: Special Weather Statements and Warnings
Environment Canada issues a hierarchy of watches, advisories, and warnings. A Special Weather Statement provides information on significant weather but doesn't meet warning criteria. A Watch means conditions are favourable for severe weather. An Advisory means hazardous but non-severe conditions are expected. A Warning means severe or dangerous weather is imminent or occurring.
Step 6: Using the UV Index
The UV Index is included in warm-season forecasts. A UV Index of 1-2 is Low (no protection needed), 3-5 is Moderate (protection recommended), 6-7 is High (protection essential), 8-10 is Very High, and 11+ is Extreme. Apply sunscreen of SPF 30+ for any UV Index above 3.
