Wind chill in the context of "Iditarod Trail Sled Dog Race"

Climate in Canada varies widely from region to region. In many parts of the country, particularly in the interior and Prairie provinces, winters are long, very cold, and feature frequent snow. Most of Canada has a continental climate, which features a large annual range of temperatures, cold winters, and warm summers. Daily average temperatures are near −15 °C (5 °F), but can drop below −50 °C (−58 °F) with severe wind chills. In non-coastal regions, snow can cover the ground for almost six months of the year, while in parts of the north snow can persist year-round. Coastal British Columbia has a more temperate climate, with a mild and rainy, cloudy winter. The British Columbia Southern interior has a semi-desert climate in many locations, with long warm to hot, dry summers, and short moderate winters. The immediate area adjacent to the town of Ashcroft, features Canada's only true desert. On the east and west coasts, average summer high temperatures are generally in the low 20s °C, while between the coasts, the average summer high temperature ranges from 25 to 30 °C (77 to 86 °F), with temperatures in some interior locations occasionally exceeding 40 °C (104 °F).

Much of Northern Canada is covered by ice and permafrost; however, the future of the permafrost is uncertain because the Arctic has been warming at three times the global average as a result of climate change in Canada. Canada's annual average temperature over land has warmed by 1.7 °C (3.1 °F), with changes ranging from 1.1 to 2.3 °C (2.0 to 4.1 °F) in various regions, since 1948. The rate of warming has been higher across the North and in the Prairies. In the southern regions of Canada, air pollution from both Canada and the United States—caused by metal smelting, burning coal to power utilities, and vehicle emissions—has resulted in acid rain, which has severely impacted waterways, forest growth and agricultural productivity in Canada.

A narrows or narrow (used interchangeably but usually in the plural form), is a restricted land or water passage. Most commonly a narrows is a strait, though it can also be a water gap.

A narrows may form where a stream passes through a tilted bed of hard rock lying between two softer beds: "[i]f the hard beds are vertical, so that their outcrop does not shift as erosion proceeds, a narrows is developed". Like a dam, this "raises the water level for a short distance upriver". A narrows is also typically a good location for trapping migrating fish. Furthermore, a narrows is "an important topographical feature for wind mixing", an effect where a wind chill may form ice while the surrounding temperature remains above freezing.

Apparent temperature, also known as "feels like", is the temperature equivalent perceived by humans, caused by the combined effects of air temperature, relative humidity and wind speed. The measure is most commonly applied to the perceived outdoor temperature. Apparent temperature was invented by Robert G. Steadman who published a paper about it in 1984. It also applies, however, to indoor temperatures, especially saunas, and when houses and workplaces are not sufficiently heated or cooled.

• The heat index and humidex measure the effect of humidity on the perception of temperatures above +27 °C (81 °F). In humid conditions, the air feels much hotter, because less perspiration evaporates from the skin.
• The wind chill factor measures the effect of wind speed on cooling of the human body below 10 °C (50 °F). As airflow increases over the skin, more heat will be removed. Standard models and conditions are used.
• The wet-bulb globe temperature (WBGT) combines the effects of radiation (typically sunlight), humidity, temperature and wind speed on the perception of temperature. It is not often used, since its measurement requires the use of a globe thermometer exposed to the sun, which is not included in standard meteorological equipment used in official weather conditions reporting (nor are, in most cases, any other explicit means of measuring solar radiation; temperature measurement takes place entirely in a shade box to avoid direct solar effects). It also does not have an explicit relationship with the perceived temperature a person feels; when used for practical purposes, the WBGT is linked to a category system to estimate the threat of heat-related illness.

Since there is no direct measurement of solar radiation in U.S. observation systems, and solar radiation can add up to 15 °F (8.3 °C) to the apparent temperature, commercial weather companies have attempted to develop their own proprietary apparent temperature systems, including The Weather Company's "FeelsLike" and AccuWeather's "RealFeel". These systems, while their exact mechanisms are trade secrets, are believed to estimate the effect of solar radiation based on the available meteorological data that is reported (such as UV index and cloud cover).