Canada Climate – Sep 2026September 2026 Update

Novarupta (Katmai) eruption

The largest volcanic eruption anywhere in the world in the 20th century - 13 km3 of magma, about thirty times the 1980 Mount St. Helens eruption - at Novarupta in Alaska on 6-8 June 1912. Ash reached 100,000 ft and cooled the Northern Hemisphere by roughly 0.3°C over 1912-13. Unlike a tropical eruption such as Pinatubo, a high-latitude eruption's haze stays in its own hemisphere, so it did little to the Southern Hemisphere.

Smithsonian Global Volcanism Program, Alaska Volcano Observatory, National Park Service, Oman et al. 2005

Post-WWII industrial expansion begins

After the Second World War, coal and oil use grew rapidly across Europe, North America and the Soviet Union. Global sulphur dioxide emissions rose from about 30 to about 130 million tonnes a year by 1980, and the sulphate haze they formed masked part of the greenhouse warming underneath - the effect known as 'global dimming'.

Klimont et al. 2013

How much ENSO really controls Canada's climate

ENSO matters in Canada more than its national average suggests. El Niño brings milder winters to western and central Canada and La Niña colder ones, according to Environment and Climate Change Canada, but the Atlantic provinces and the Arctic respond weakly, so the all-Canada figure dilutes the signal - in this site's data ENSO explains only about 9% of the year-to-year swing in Canada's January-March temperatures.

NOAA CPC

The 1955-56 La Niña

Canada's temperatures for January-March 1956 ran -0.6°C against the 1961-90 average - the cool January-March that La Niña usually brings here.

ONI -1.6°C · RONI -1.4°C

NOAA CPCENSO Tracker

Keeling Curve begins

Charles David Keeling begins continuous measurements of atmospheric CO₂ at Mauna Loa Observatory in Hawaii, starting at about 315 ppm. The record has risen every year since and is now the longest unbroken direct measurement of CO₂ anywhere - the 'Keeling Curve'.

NOAA GMLGreenhouse Gases

Agung eruption

Agung's eruption in Bali put a veil of sulphate haze into the stratosphere that cooled global temperature by about 0.3°C over 1963-66.

Smithsonian Global Volcanism Program, NOAA Global Monitoring Laboratory

The 1972-73 El Niño

Canada's temperatures for January-March 1973 ran +0.9°C against the 1961-90 average - the warm January-March that El Niño usually brings here.

ONI +1.8°C · RONI +2.0°C

NOAA CPCENSO Tracker

1972: Canada's coldest year

1972 is Canada's coldest year since national records began in 1948, 1.9°C below the reference average, and it is also the coldest in this site's 1950-2025 record. No year since has come close.

Government of Canada

The 1973-74 La Niña

Canada's temperatures for January-March 1974 ran -2.5°C against the 1961-90 average - the cool January-March that La Niña usually brings here.

ONI -2.0°C · RONI -1.9°C

NOAA CPCENSO Tracker

The 1975-76 La Niña

Canada's temperatures for January-March 1976 ran -0.7°C against the 1961-90 average - the cool January-March that La Niña usually brings here.

ONI -1.6°C · RONI -1.1°C

NOAA CPCENSO Tracker

Pacific Decadal Oscillation flips to a warm phase

The Pacific Decadal Oscillation - a slow natural cycle in North Pacific sea temperatures - switches from its cool to its warm phase in 1976-77. The change was abrupt enough to be called the 1976-77 Pacific Climate Shift: it warmed Alaska and the west coast of North America, and reorganised North Pacific fisheries.

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Global SO2 emissions peak

Global sulphur dioxide emissions peak at about 130 million tonnes a year, then begin a long decline as Europe, North America and Japan clean up their air. As the aerosol mask thins, the rate of global warming picks up through the 1980s.

Klimont et al. 2013

El Chichón eruption

A sulphur-rich eruption in Mexico whose aerosol cloud stayed in the stratosphere for more than two years, cooling the Northern Hemisphere by about 0.2°C.

Smithsonian Global Volcanism Program

1982-83 El Niño

Canada's temperatures for January-March 1983 ran +0.3°C against the 1961-90 average - the warm January-March that El Niño usually brings here. On NOAA's Relative Oceanic Niño Index this is the strongest El Niño since 1950.

ONI +2.1°C · RONI +2.4°C

NOAA CPC, NOAA CPC (2)ENSO Tracker

The Antarctic ozone hole is discovered

British Antarctic Survey scientists Joe Farman, Brian Gardiner and Jon Shanklin publish their Halley and Faraday measurements on 16 May 1985, showing October ozone over Antarctica had fallen to about two-thirds of earlier decades. The cause is traced to chlorofluorocarbons, and the finding triggers the fastest international environmental response on record.

Nature, UKRI

The Montreal Protocol

Signed in 1987 to phase out ozone-depleting chlorofluorocarbons, the Montreal Protocol turned out to be one of the most consequential climate treaties ever agreed. CFCs are potent greenhouse gases in their own right, and NOAA estimates the Protocol prevented up to 2°C of warming by 2100 - around 1°C from the emissions avoided, and up to 1°C more by sparing forests and other carbon sinks from increased ultraviolet radiation.

NOAA, Wikipedia

CO₂ crosses 350 ppm

Atmospheric CO₂ passes 350 ppm. In the same year James Hansen told a US Senate committee that global warming was already detectable, the moment it entered mainstream politics. Twenty years later, in 2008, Hansen proposed 350 ppm as the safe upper limit - a level the world had already left behind.

NOAA GMLGreenhouse Gases

The 1988-89 La Niña

Canada's temperatures for January-March 1989 ran -1.1°C against the 1961-90 average - the cool January-March that La Niña usually brings here.

ONI -1.9°C · RONI -1.9°C

NOAA CPCENSO Tracker

Daytime warming catches up with the night-led pattern

Across 1961-90, 81% of the world's land saw nights warming faster than days. Across 1991-2020 the pattern reversed: 70% saw days warming faster, as the industrial haze that had been dimming daytime sunshine was cleaned up. The study compares two fixed thirty-year windows; measured as a turning point, this site's own global series turns around 1982.

Zhong et al. 2023

Mount Pinatubo erupts

Pinatubo's cooling is only faintly visible in Canada's own record. 1992, the year after the June 1991 eruption, ranks 18th-coldest of the 76 years there. A single large eruption can hold temperatures down for two or three years; it cannot reverse the trend.

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Atlantic Multidecadal Oscillation flips to a warm phase

The Atlantic Multidecadal Oscillation - a slow natural cycle in North Atlantic sea temperatures, roughly 60-70 years long - flips to its warm phase in 1995. Warm phases are linked to more active Atlantic hurricane seasons, wetter summers in parts of north-west Europe and more frequent drought in the central and western United States.

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1997-98 El Niño

Canada's temperatures for January-March 1998 ran +1.8°C against the 1961-90 average - the warm January-March that El Niño usually brings here. It is often treated as the textbook strong El Niño.

ONI +2.4°C · RONI +2.3°C

NOAA CPC, NOAA NCEIENSO Tracker

The Great Ice Storm, 1998

For five days in January 1998 freezing rain coated eastern Ontario and southern Quebec in ice, bringing down power lines and pylons. About 1.4 million customers in Quebec and 230,000 in Ontario lost power, some for weeks; as many as 35 people died and the army deployed 16,000 troops. The year as a whole was mild: 1998 is Canada's 5th-warmest in this site's 1950-2025 record, helped by the very strong 1997-98 El Niño.

The Canadian Encyclopedia, Veterans Affairs Canada

The 1999-2001 La Niña

Canada's temperatures for January-March 2000 ran +2.5°C against the 1961-90 average - the opposite of the cool January-March La Niña usually brings here.

ONI -1.5°C · RONI -1.6°C

NOAA CPC ONI

Pacific Decadal Oscillation flips back to a cool phase

The Pacific Decadal Oscillation - a slow natural cycle in North Pacific sea temperatures - flips back to its cool phase around 1998-99. The cool phase that followed is one reason global surface warming appeared to slow in the 2000s, as more heat went into the deep Pacific.

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2009-10 El Niño

Canada's temperatures for January-March 2010 ran +5.2°C against the 1961-90 average - the warm January-March that El Niño usually brings here.

ONI +1.5°C · RONI +1.5°C

NOAA/IRI ENSO archiveENSO Tracker

Global heatwave days sharply accelerate

Canada's own heatwave days - days in warm spells well above the local norm - rose from a 1961-90 average of 6.0 a year to 14.0 in 2016-25 - more than double. Worldwide, heatwave days have roughly doubled each decade since 2010, as the whole temperature distribution has shifted upwards.

Learn more →Heatwave Days

The 2010-2012 La Niña

Canada's temperatures for January-March 2011 ran +0.9°C against the 1961-90 average - the opposite of the cool January-March La Niña usually brings here.

ONI -1.6°C · RONI -1.6°C

NOAA CPC ONI

2010: Canada's warmest year

2010 was Canada's warmest year since national records began in 1948 - 3.0°C above normal - after its mildest winter on record. The Vancouver Winter Olympics, in February, had rain instead of snow and temperatures above 5°C for weeks. It is also Canada's warmest year in this site's 1950-2025 record.

CBC News, CBC News (2)

CO₂ crosses 400 ppm

Atmospheric CO₂ passes 400 ppm at Mauna Loa on 9 May 2013 - a level the planet had not seen for 3-5 million years, since the Pliocene, when sea levels were many metres higher.

NOAA GMLGreenhouse Gases

The southern Alberta floods, 2013

In June 2013 heavy rain on the Rocky Mountain foothills, falling onto late snow, sent the Bow and Elbow rivers through Calgary and neighbouring towns. About 100,000 people were evacuated, and at around C$5 billion it was, until the Fort McMurray fire, the costliest disaster in Canadian history.

City of Calgary, The Weather Network

2015-16 El Niño

Canada's temperatures for January-March 2016 ran +3.4°C against the 1961-90 average - the warm January-March that El Niño usually brings here. By the raw ONI index it was the strongest El Niño ever measured - a reminder that a strong index does not guarantee a strong local outcome.

ONI +2.6°C · RONI +2.3°C

NOAA CPCENSO Tracker

2015-2025: the eleven warmest years on record

Globally, the eleven warmest years on record have all happened since 2015. Canada's own record is a looser fit - five of its eleven warmest fall in that span, with 2012, 2010, 2006, 2001, 1998 and 1981 outside it. Its warmest year is 2010.

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The Fort McMurray wildfire, 2016

On 3 May 2016 a wildfire swept into Fort McMurray, Alberta, forcing about 88,000 people to leave - the largest wildfire evacuation in the province's history. At around C$9 billion it remains the costliest disaster in Canadian history.

PreventionWeb, Climate Central

COVID-19 lockdowns - CO₂ emissions dip

Global fossil CO₂ emissions fell about 5.8% in 2020, from 37.0 to 34.8 billion tonnes, yet atmospheric CO₂ still rose 2.5 ppm - the dip barely registers in the atmospheric record. Emissions were back to pre-pandemic levels by 2022.

Le Quéré et al. 2020

Low-sulphur shipping fuel rule (IMO 2020)

New international shipping rules cut the sulphur allowed in ship fuel from 3.5% to 0.5% almost overnight, removing about 8 million tonnes of sulphur dioxide a year. With less sulphate haze over the oceans, it may have added around 0.1°C of warming by 2023-24.

Gettelman et al. 2024

The 2020-2023 'triple-dip' La Niña

Canada's temperatures for January-March 2021 ran +2.7°C against the 1961-90 average - the opposite of the cool January-March La Niña usually brings here.

ONI -1.1°C · RONI -1.5°C

WMO, WMO (2)ENSO Tracker

Canada's 49.6°C: Lytton, June 2021

On 29 June 2021 the village of Lytton, British Columbia, reached 49.6°C - the highest temperature ever measured in Canada, and 4.6°C above the previous national record, set in 1937. It was the third day running that Lytton broke the record. The next day a wildfire destroyed most of the village.

CBC News, Royal Meteorological Society

2023-24 El Niño

Canada's temperatures for January-March 2024 ran +3.2°C against the 1961-90 average - the warm January-March that El Niño usually brings here. Globally it helped produce the record temperatures of 2023 and 2024.

ONI +2.0°C · RONI +1.4°C

NOAA CPCENSO Tracker

Canada's record wildfire season, 2023

Canada's 2023 fires burned about 18.4 million hectares - two and a half times the previous record, set in 1995, and more than six times the average of the past decade. Smoke reached as far as New York and western Europe.

Natural Resources Canada, NASA Earth Observatory