Atmospheric Pressure, also called barometric pressure, is the force per unit area exerted by the atmosphere as a consequence of its weight. It is equal to the weight of a vertical column of air of a u [..]

Dust that is raised by the wind, to moderate heights above the ground. Visibility at eye level may be reduced to 1 km

Snow particles violently stirred up by wind to sufficient heights above the ground to reduce visibility to 10 km

An absence of wind flow or any other air motion.

A temperature scale where water at sea level has a freezing point of 0 °C (Celsius) and a boiling point of +100 °C

The historical record and description of average daily and in seasonal weather events that help describe a region. Statistics are generally drawn over several decades. Climatology, or the study of cli [..]

Also referred to as station ID or station number, the climate ID is a 7 digit number assigned by the Meteorological Service of Canada to a site where official weather observations are taken, and serve [..]

A visible collection of minute particle matter, such as water droplets and/or ice crystals, in the air. A cloud forms in the atmosphere as a result of condensation of water vapour. Condensation nuclei [..]

Normals for some elements are derived from less than 30 years of record but can still be considered useful. The minimum number of years used are indicated by a "code" defined as:

Cooling degree-days for a given day are the number of degrees Celsius that the mean temperature is above 18 °C