How much heating does a home need at my BC property, and how long is the growing season?

What the answer means

What a degree day is

A degree day is one degree of a day's mean temperature below or above a base, added up over the year. Heating degree days below 18 °C follow how much a home needs heating: a place with 5,000 needs roughly half again the heat of one with 3,300, for the same house. Growing degree days above 5 °C (10 °C for warm-season crops such as corn and grapes) follow how much warmth plants get to grow.

Heating degree days

The yearly sum of how far each day's mean temperature falls below 18 °C. Heating bills follow it closely: for the same house, the fuel or power for heat grows about in step with the heating degree days. Victoria has under 3,000, Prince George about 5,000, Fort Nelson over 6,500.

Heat pumps

Heating degree days say how much heat a house needs over a winter, not how cold the coldest nights get. For a heat pump, ask also about the lowest temperatures: the report and each place's page give the lowest recorded from 1991 to 2020.

Growing degree days

The yearly sum above 5 °C follows how much warmth cool-season plants (grass, grains, hay, most vegetables) get; above 10 °C, warm-season crops such as corn, tomatoes and grapes. The Okanagan's south end passes 1,400 above 10 °C; much of the north stays near or under 600.

Which station

A report and a place's page take the nearest station within 30 km, 1991–2020 where ECCC publishes it, else 1981–2010. A place without a station, or whose station's normals carry no degree days, says so on its page.

Elevation and setting

A lot a few hundred metres above the station has more heating and fewer growing degree days than the station; a lakeshore evens both out. The report gives the lot's elevation against the station's.

Fewer years

Most stations' degree days rest on 15 to 25 of the 30 years. They're marked with an asterisk: treat them as a rougher guide.

Degree days are a station's averages, read by us for the nearest station; the lot itself can differ, and recent years have run warmer than the normals in much of BC, with fewer heating and more growing degree days. Confirm with the seller for the past year's heating bills, an energy advisor about the home's heating, and a local nursery or the regional agrologist about what grows there before you buy or build.

Source: Canadian Climate Normals 1991-2020 and 1981-2010, Environment and Climate Change Canada (Open Government Licence – Canada).

By place

236 of BC's 319 places have degree days in their nearest station's normals within 30 km, listed by name.

* Based on fewer years than the WMO standard: these figures rest on at least 20 or 15 of the 30 years, short of the World Meteorological Organization's standard of nearly all of them. ECCC publishes them as normals; treat them as a rougher guide.

The other 83 places have no station within 30 km, or their station's normals carry no degree days; their pages say which. A dash means the normals don't carry that figure. Distances are from the town centre (in an electoral area, its main settled place).

Source: Canadian Climate Normals 1991-2020 and 1981-2010, Environment and Climate Change Canada (Open Government Licence – Canada).