Extreme cold warning
As of April 8, 2014, Environment Canada replaced the Wind Chill Warning with an Extreme Cold Warning. In the older system a wind chill warning for Southern Ontario and Atlantic Canada was issued when the wind chill dropped to -35. Thus a temperature of −37 °C (−35 °F) with no winds would not require a warning be issued. Under the new system the extreme cold warning is issued based on either the temperature or the wind chill being a certain value for at least two hours. The values range from −30 °C (−22 °F) in the south to −55 °C (−67 °F) in parts of the Arctic.
Ranges for issuing an extreme cold warning
An extreme cold warning is issued when the following temperatures are expected to last for at least two hours:
- South-Central Ontario and Southwestern Ontario issued at −30 °C (−22 °F)
- Southeastern Ontario, the Southern Interior of British Columbia, the British Columbia Coast and Atlantic Canada (excluding Labrador) issued at −35 °C (−31 °F)
- Quebec (excluding northern Quebec) issued at −38 °C (−36 °F)
- Northern Ontario (excluding the far north), Central Interior of British Columbia and the Prairies (Alberta, southern Manitoba, southern Saskatchewan) issued at −40 °C (−40 °F)
- Far northern Ontario, northern Manitoba (excluding northeastern Manitoba), northern Saskatchewan, Northern Interior of British Columbia and Labrador issued at −45 °C (−49 °F)
- Northern Quebec (excluding Nunavik) issued at −48 °C (−54 °F)
- Yukon, Northwest Territories (excluding Paulatuk, Sachs Harbour, Ulukhaktok), Baffin Island, and northeastern Manitoba issued at −50 °C (−58 °F)
- Nunavik issued at −52 °C (−62 °F)
- Northwest Territories (Paulatuk, Sachs Harbour, Ulukhaktok only) and Nunavut (excluding Baffin Island) issued at −55 °C (−67 °F)
In the United States an extreme cold warning was an experimental weather warning issued by the National Weather Service in North Dakota, South Dakota, and Minnesota. The warning was issued if the temperature fell to −35 °F (−37 °C) or colder with a wind of less than 5 mph (8 km/h; 2 m/s). It was an experimental advisory for when the air temperature was dangerously cold, but the wind was too little to warrant a Wind Chill Watch or Warning.
The Extreme Cold Warning was used from January 10, 2011 to April 15, 2011. It was discontinued beginning with the 2011-12 winter storm season. Only five Extreme Cold Warnings were issued: one for Burleigh County, three for areas outside of the Bismarck–Mandan metropolitan area, and one for West Glacier, Montana
In a partner webinar on October 30, 2018, the National Weather Service announced that based on survey feedback, the Extreme Cold Warning and the Wind Chill Warning will be consolidated into the Extreme Cold Warning, meaning that this product would once again be issued on a regular basis. This change was hinted to take effect sometime in 2021, accounting for NWS software upgrades. 
URGENT - WEATHER MESSAGE National Weather Service Missoula MT 237 PM MST Sun Mar 3 2019 MTZ002-003-007-043-041800- /O.NEW.KMSO.EC.W.0001.190304T0300Z-190304T1800Z/ West Glacier Region-Flathead/Mission Valleys- Butte/Blackfoot Region-Potomac/Seeley Lake Region- 237 PM MST Sun Mar 3 2019 ...EXTREME COLD WARNING IN EFFECT FROM 8 PM THIS EVENING TO 11 AM MST MONDAY... The National Weather Service in Missoula has issued an Extreme Cold Warning, which is in effect from 8 PM this evening to 11 AM MST Monday. * TEMPERATURES...15 to 30 below zero, with local areas down to 40 below zero. * TIMING...Late this evening through mid morning Monday. * IMPACTS...Local power outages and broken pipes are possible due to the extreme cold. PRECAUTIONARY/PREPAREDNESS ACTIONS... An Extreme Cold Warning means that dangerously low temperatures are expected for a prolonged period of time. Frostbite and hypothermia are likely if exposed to these temperatures, so make sure a hat, facemask, and heavy gloves or mittens are available. && $$
- Environment Canada. "Wind Chill Hazzards". Archived from the original on December 17, 2005.
- Extreme Cold Warning
- "National Weather Service Plans to Issue 'Extreme Cold Warnings'". Archived from the original on 2013-06-16.
- "NWS To Experiment With 'Extreme Cold' Warnings".
- "Experimental Cold Warning Feedback Needed".
- "NWS Tests Extreme Cold Warning". Archived from the original on 2013-06-09.
- "National Weather Service ditching 'extreme cold' warnings".
- "National Weather Service Public Information Statement PNS18-11" (PDF). Retrieved February 1, 2019.
- "Update on Winter Weather Initiatives Partner Webinar" (PDF). Retrieved February 1, 2019.