Refers to how the outdoor air is expected to feel in degrees Celsius when actual temperature and relative humidity are combined (see humidex) or when actual temperature and wind are combined (see windchill).
Wind is the horizontal movement of air in relation to the earth's surface. Wind direction tells where the wind is blowing from. For example, a "north wind" is coming from the north and is blowing towards the south. There are four components of wind that are measured: direction, speed, character (i.e. whether it's a gust or a squall) and shifts.
A sudden significant increase in, or rapid variation of wind speed. Usually a gust lasts less than twenty seconds.
Sunrise occurs the instant the upper edge of the disk of the sun appears above the horizon. This time is given assuming that conditions are clear and the region is level. Depending on weather, local land formations and obstructions, the sun may not be visible at the exact time of sunrise.
Sunset occurs when the upper edge of the disk of the sun disappears below the horizon. This time is given assuming that conditions are clear and the region is level. Depending on weather, local land formations and obstructions, the sun may appear to set earlier than the official sunset time.
Relative humidity is a percentage of water vapour per area at a specific temperature. Relative humidity is calculated at all times of the year, but the humidex is usually only given in the warmer months from May to September.
Relative humidity can be calculated using various methods and instruments. It is a calculation to find out how many grams of water vapour can be held at a given temperature. Usually, the warmer the air, the higher its capacity for holding water vapour. Each specific temperature has a holding limit for water, and the actual amount of water held in the air at the time of measurement can be represented as a percentage.
For example, if a parcel of air at 20ºC has a limit or capacity of 16 grams of water vapour and 16 grams of water vapour is measured, the air's holding capacity is at its maximum and the relative humidity (RH) of the air is said to be 100%. Take the same air with 8 grams of water vapour and your RH is 50%.
The force per unit area exerted by the weight of the atmosphere above a point on or above the earth's surface. Also known as atmospheric pressure or barometric pressure.
Visibility is defined as the greatest distance an object can be seen and identified. It is usually a visual estimate and is reported as prevailing visibility -- the maximum visibility common to one half or more of the horizon circle. When visibility is uniform in all directions, prevailing visibility and visibility are the same. When visibility is not uniform in all directions, you can determine prevailing visibility by dividing the horizon circle into sectors of visibility. Estimate the highest visibility common to one half or more of the horizon circle.
The maximum visibility on a clear day is 11 kilometres (7 miles), after which a flat ground horizon will fall away to a point that surface conditions cannot be observed. In order to report visibility beyond this distance visibility markers are used. These markers are measured and could include mountains/hills, tree lines and microwave towers. The visibility is determined by the weather observer at an airport or weather station. The observer reports how far away objects can be identified without obstruction.
Ceiling is a measurement primarily used by the aviation industry. The ceiling is the height of the lowest layer of broken or overcast clouds. Ceiling is reported in feet, which is the standard for the aviation industry.
| Sunday, February 12 | Monday, February 13 | Friday, February 17 | |
|---|---|---|---|
|
Variable cloudiness |
Sunny |
Cloudy with sunny breaks |
|
| Max Temp. | -14°C | -13°C | 5°C |
| Wind | 20km/h | 15km/h | 10km/h |
| P.O.P. | 20% | 20% | 30% |
Improve your home's wall and attic insulation. Adding insulation is one of the most effective ways to reduce heating costs. Some older homes don't even have insulation between the walls.
If your furnace is older than 5 years be sure to get it checked every year.
The white line on the graph represents the normal number of heating degree days for each day in the 14-day period. The yellow line on the graph represents the forecasted number of heating degree days for each day in the 14-day period.
When the yellow line is above the white line you may see an increase in your heating bill as a result of cold temperatures. When the yellow line is at or below the white line your heating bill will likely be normal or slightly cheaper.