Natural Features of the North

Arctic Circle - What is it?

The Arctic Circle is the line of latitude around the top of the world at approximately 66 degrees, 33' north of the equator. It is the southernmost point at which sun does not set at summer solstice (June 21st), or rise at winter solstice (December 21st), meaning that it has at least one day of the "Midnight Sun".

Midnight Sun:

Summer hours of daylight increase with proximity to the North Pole, because the north pole tilts toward the sun in summer. In the far north, the sun rises and sets at a shallow angle to the horizon. This makes for long periods of dawn and dusk. The "longest" day is June 21st, the Summer Solstice. The "shortest" day of the year within the northern hemisphere is December 21st, the Winter Solstice. This is when the northern latitudes of the planet are tilted furthest away from the light and heat of the sun.

Communities north of the Arctic Circle experience extreme contrasts between summer and winter. There are 57 days in summer when the sun does not set at all, and 30 days in the winter when the sun does not rise. Summer temperatures of 35º C contrast with minus 45º C during the 24 hour darkness, in December and January. Soaking up the long summer sunlight, and warmed by southern breezes, the Mackenzie Valley stays several degrees warmer than the tundra and mountains. It is not unusual for Inuvik to be hotter than Edmonton or Vancouver on a July afternoon.

Typical hours of daylight for selected NWT communities:
 

What is the Arctic?

The Arctic climate is defined as the area in which the average mean daily temperature does not exceed 10º C. The temperature, along with geography affects the tree line, which extends roughly northwest from the Manitoba border to Inuvik. Everything north of the tree line is arctic in terms of geography and climate.
The main characteristics of the Arctic are extreme differences between the seasons, and low levels of solar energy. Because of the earth's curvature, sunlight strikes the Arctic at a lower angle than nearer the equator, and the energy in those rays is spread over a larger area. This lowers the amount of heat received. In addition, some solar energy is lost when the rays bounce off the atmosphere, and some is absorbed as it travels a greater distance through the atmosphere.

Snow covers the ground for eight months of the year, usually accumulating from October through November. However, in this region snowfall is less than 75 cm annually. On average, there is only 12-25 cm of rain during June, July and August. Parts of the Arctic can be called desert - this is one of the driest regions in the world.
When the ground is covered by snow and ice, up to 80% of solar energy is reflected back into space. Arctic winters would be even colder than they currently are, if warmth was not redistributed from other parts of the earth. In summer, the amount of solar energy plants receive in a 24 hour period of sunlight equals the amount the equator receives in its 12 hour day.

What is the Sub Arctic?

Winters in the sub arctic are longer and colder than in southern Canada. Temperatures in this region fall below 0º C for seven months of the year, October to April. Extreme temperatures such as minus 57º C have been recorded, but this is rare.
In Yellowknife, the average daily temperature from November to March is minus 22º C. The average temperature in Yellowknife during June, July and August is 14º C. Extreme summer temperatures in the Mackenzie Valley, such as 36º C, are rare. Proximity to water can have a noticeable effect on the frost-free period which ranges from 50 to 100 days.
The shorter growing season is offset by long hours of daylight. There are 20 hours of daylight in June in the southern Mackenzie and the area averages eight hours of bright sunshine a day throughout the summer.
Annual precipitation in the Mackenzie Basin is light, ranging from 23 to 38 cm. Snowfalls average about 127 cm. Rainfall is minimal in the north Mackenzie, near the arctic coast, averaging 6 cm.

The Northern Seasons

The seasons, with the exception of winter are shorter in the Northwest Territories. Winter is from November to March, Spring is from April to May, Summer is from June to August, and Fall is from September to October. The temperature range differs significantly according to the time of year. During the summer the temperature can go as high as 35º C, while in the winter it can plummet to minus 45º C.

Typical temperature (in oC & oF) on a quarterly basis for selected NWT communities:

* Source: Environment Canada

Time Zone:

All of the NWT is located in the Mountain Time Zone, the same as Alberta, Montana, Colorado, Arizona and New Mexico. Unlikely as it seems, the Mackenzie Delta is further west than Vancouver, at a longitude one third of the way between Seattle and Hawaii; but our clocks are set to Mountain Time. This is really noticeable during daylight savings time in the summer - midnight by the clock is really only nine o'clock by the sun, which is reluctant to set anyway.