A Few Clouds

Clear skies are dominant with scattered clouds.

A Mix of Sun and Clouds

At times there will be more clouds than sun, and at other times there will be more sun than clouds.

Clear

Skies will be almost totally clear, perhaps with a few small light clouds visible. Clear is the nighttime term equivalent to "Sunny".

Clearing

Most of the sky will be covered in clouds, but you will see more and more sunshine throughout the forecast period.

Clouding Over

Skies will be mostly clear, but more and more cloud cover will develop throughout the forecast period. The sky will become completely overcast before the end of the forecast period.

Cloudy

No sunshine visible.

Cloudy with Flurries

The cloud cover will be as described for "Cloudy", and the precipitation light. The flurries will be short-lived and intermittent, and will not amount to any significant accumulation on the ground. Visibility will be reduced, but roadways will not generally be slippery.

Cloudy with Freezing Rain

The sky condition will be as described above, with precipitation consisting of supercooled liquid raindrops that instantly freeze on contact. Visibility will generally be good, but roadways will be extremely slippery and dangerous. Freezing rain will create a layer of ice on bare surfaces and existing snow.

Cloudy with Isolated Flurries

The cloud cover will be as described for "Cloudy" and the precipitation very light. The flurries will be brief and intermittent, and will not amount to any significant accumulation on the ground. Visibility will be reduced, but roadways will not generally be slippery.

Cloudy with Light Rain

The sky will be overcast and the precipitation will be strong enough to get things wet in a short time. The rain will interfere with outdoor activities. Puddles will form quickly and water may run down the expressways, causing slippery road conditions. Precipitation will persist throughout the forecast period.

Cloudy with Light Snow

The cloud cover will be as described for "Cloudy", the precipitation light. The snow will be continuous but will not usually amount to any significant accumulations for the forecast period. Visibility will be reduced and roadways can be slippery, depending on the duration of the snow.

Cloudy with Scattered Thundershowers

The sky will be cloudy, with some showers or light rain possible; thunder and lightning will be associated with the precipitation. The showers or rain may be heavy for short periods of time.

Cloudy with Showers

The sky will be overcast and the strength of the precipitation will be light. The showers will be intermittent, and will generally interfere with outdoor activities. The ground will get wet.

Cloudy with Thundershowers

The sky will become cloudy with a few showers or light rain possible; thunder and lightning will be associated with the precipitation. The showers or rain may be heavy for extended periods of time.

Cloudy with Thunderstorms

The sky will be cloudy, with showers or light rain possible; thunder and lightning will be associated with the precipitation. The showers or rain will be heavy for extended periods of time.

Cloudy with Wet Flurries

The sky condition will be as for "Cloudy", with intermittent precipitation. The snow will be partially melted before reaching the ground, and will accumulate as a light dusting of wet sticky snow if it does not melt instantly on contact. Visibility will be reduced, but roadways will generally not get slippery.

Drifting Snow

Created when winds lift snow from the surface and blow it to heights less than 2 meters. No additional snow will be falling and visibility will not generally be reduced, but roadways can still get slippery.

Drizzle

Heavy mist or light, fine, continuous rain that will fall slowly, reducing visibility somewhat more than light rain. Water droplets will be between 0.2mm and 0.5mm in size. Drizzle can often be confused with light rain, however drizzle's water droplets will be smaller in size than those of rain.

Flurries

Intermittently falling snow, generally short-lived. Flurries are the solid equivalent of "Rain Showers".

Fog

A cloud with its base at the Earth's surface. Visibility is reduced to less than 1 km.

Foggy

Fog is expected to form throughout the countryside, causing reduced visibility over large areas. The fog will generally be slow in breaking up, and may eventually result in a mixture of sun and clouds as the fog lifts and breaks up. Foggy conditions may be forecast after rain or showers overnight and into the early morning hours.

Fog Patches

Some fog is expected to form, but will generally be restricted to low lying areas. It may cause reduced visibility if encountered. Fog patches generally break up through the first part of the morning if they form overnight. They may be forecast after rain or showers at any time of the day, but generally fog occurs late at night or in the early morning hours.

Freezing Drizzle

Very fine supercooled liquid rain drops with a diameter of less than 0.5mm.

Freezing Rain

Supercooled liquid raindrops that freeze on contact with the ground. Freezing rain will form a layer of ice on any surface instantly.

Gradual Clearing

Most of the sky will be covered in clouds, but you will see more and more sunshine throughout the forecast period. It may take the entire period for the sky to become less than half covered in clouds.

Hazy

The sky will appear to be covered in a very light fog when viewed off in the distance. Haze is created when fine dust particles disperse through a portion of the atmosphere. It is generally not noticeable when observed from directly above or below. Typically, haze does not impair visibility to any great extent.

Heavy Rain

The sky will be overcast and the precipitation continuous, strong enough to get things wet very quickly. There may be minor flooding of storm drains and roadways if the precipitation continues for very long. Heavy rain causes reduced visibility while driving.

Humidex

A calculation combining air temperature and relative humidity, given in degrees Celsius. It represents the heating effect felt due to a lack of body moisture evaporation, and gives the average person a "feeling" for how hot and stuffy the air is. Humidex is given only in the summer months.

Increasing Cloudiness

Skies will be mostly clear, but more and more cloud cover will develop throughout the forecast period. It will not become completely overcast before the end of the forecast period.

Mainly Clear with a Chance of Showers

The sky is expected to be less than half covered with clouds, but there still may be brief periods of precipitation, generally occuring in the early evening.

Mainly Cloudy with Scattered Showers

Cloud cover as for "Mainly Cloudy", with light precipitation of short duration. The showers will come and go, and generally interfere with outdoor activities. The ground will get wet.

Mainly Sunny

Clear, with a small area of clouds visible. Cloud cover will be between 1/10 and 3/10.

Mainly Sunny with a Chance of Showers

The sky is expected to be less than half covered with clouds, but there still may be brief periods of precipitation, generally occuring in the late afternoon.

Mainly Sunny with a Chance of Thunderstorms

The sky is expected to be less than half covered with clouds, but there still may be brief periods of showery precipitation with thunder and lightning, generally occuring at the end of the afternoon.

Mixed Precipitation

Mixed precipitation is a combination of liquid and solid precipitation, and is generally continuous. The precipitation falling must either consist of rain, snow and ice pellets, or rain and ice pellets. Some freezing rain can be mixed in as well. The concentration of precipitation types falling can change throughout the forecast period and is not quantified. Visibility will be reduced and roadways can be extremely slippery. A small accumulation of snow and/or ice pellets can be expected, depending on the proportion of solid to liquid precipitation.

Partly Cloudy

Clouds dominate, with little clear sky showing. Cloud cover will be between 6/10 and 9/10.

Rain

The sky will be overcast and the precipitation continuous, with water droplets greater than 0.5mm in size. Things will get wet very quickly. The rain will interfere with outdoor activities. Puddles will form quickly, water will generally run down expressways, and reduced visibility while driving may be a problem.

Rain and Snow

A mix of both rain and snow is expected for the forecast period. The precipitation will be continuous. The concentration of rain and snow can change throughout the forecast period and is not quantified. Small accumulations of snow can sometimes occur depending on the proportion of snow to rain. Visibility will be reduced and roadways can be very slippery.

Rain Showers

Intermittently falling rain, generally short-lived.

Relative Humidity

The ratio between the amount of water vapour in the air compared to the maximum amount of water vapour the air can hold, at a given temperature and pressure.

Snow

The sky will be overcast and the snow continuous. The snow can amount to significant accumulations but usually will not exceed 3cm during the forecast period. Visibility will be reduced, roadways slippery, and snow may accumulate on roadways with the absence of salt trucks. If more than 3cm of snow is expected to fall within a forecast period, the snow forecast will call for "3 to 5 cm of snow", "5 to 10 cm of snow", or "more than 10 cm of snow".

Snowsqualls

Snowsqualls are created when winds blow over an open body of water. Downwind and onshore, the squalls can carry strong winds and produce significant accumulations of snow. Visibility will be reduced, roadways slippery, and snow may accumulate on roadways with the absence of salt trucks. Snowsqualls are typically very localized phenomena.

Sunny with Cloudy Periods

Mostly clear, with times when about half of the sky will be covered in clouds.

Thundershowers

Intermittent rain showers with thunder and lightning, generally short-lived.

Variable Cloudiness

At times there will be more clouds than sun, and at other times there will be more sun than clouds.

Variable Cloudiness with a Chance of Thundershowers

The sky is expected to be at least half covered with clouds, with some showers possible; thunder and lightning may be associated with the showers. The showers may be quite heavy, but will be short-lived.

Variable Cloudiness with a Risk of Thundershowers

The sky is expected to be at least half covered with clouds, with a very slight chance of some showers; thunder and lightning may be associated with the showers. The showers may be heavy, but will be short-lived.

Warning

A product issued by Environment Canada forecast offices indicating that a particular weather hazard is either imminent or has been reported. A warning indicates the need to take action to protect life and property. They are issued for snowstorms, blizzards, heavy blowing snow, heavy rains, frost, cold waves, freezing rain, severe thunderstorms and strong winds - according to thresholds established for regional and public needs.

Watch

An Environment Canada product indicating that a particular hazard is possible, i.e., that conditions are more favorable than usual for its occurrence. A watch is a recommendation for planning, preparation and increased awareness (i.e. to be alert for changing weather, listen for further information and think about what to do if danger materializes).

Wet Snow

The sky will be overcast and the precipitation continuous. The snow will be partially melted before reaching the ground and can either accumulate as sticky, heavy snow or instantly melt on contact. Visibility will be reduced and roadways very slippery.

Wind Chill

Calculated only in the winter, wind chill is a calculation combining air temperature and wind speed, given in degrees Celsius. It represents the cooling effect felt due to the loss of body heat, caused by the strength of the wind and below zero temperatures.

Wind Direction

Described using one of eight different compass directions, in 45 degree increments, and indicating the direction from which the wind is coming.

Wind Speed

The average wind speed taken during an hourly five-minute window, and given in kilometers per hour.