Editing Heat wave (section)

==== North America ====
In the United States, definitions also vary by region. They usually involve a period of at least two or more days of excessively hot weather.<ref>{{cite web |url=http://www.weather.gov/glossary/index.php?word=heat+wave |title=Glossary |publisher=NOAA's National Weather Service |date=25 June 2009 |access-date=17 July 2013}}</ref> In the [[Northeastern United States|Northeast]], a heat wave is typically when the temperature reaches or exceeds {{convert|90|°F|°C|1}} for three or more consecutive days. This is not always the case. This is because the high temperature ties in with humidity levels to determine a heat index threshold.<ref>{{cite web |last=Singer |first=Stephen |title=Half the country wilts under unrelenting heat |url=http://old.news.yahoo.com/s/ap/us_hot_weather |publisher=Yahoo! News |url-status=dead |archive-url=https://archive.today/20120716024044/http://old.news.yahoo.com/s/ap/us_hot_weather |archive-date=16 July 2012 |df=dmy-all}}</ref> The same does not apply to drier climates. A heat storm is a Californian term for an extended heat wave. Heat storms occur when the temperature reaches {{convert|100|°F|°C|1}} for three or more consecutive days over a wide area (tens of thousands of square miles).<ref>{{cite web|title=Staying Cool and Safe|publisher=[[Pacific Gas and Electric Company]]|location=Oakland, California|date=24 March 2017|accessdate=26 June 2023|url=https://www.pge.com/includes/docs/pdfs/myhome/edusafety/seasonal/coolingcenters/staying_cooling_and_safe_english.pdf|archive-date=27 June 2023|archive-url=https://web.archive.org/web/20230627064913/https://www.pge.com/includes/docs/pdfs/myhome/edusafety/seasonal/coolingcenters/staying_cooling_and_safe_english.pdf|url-status=dead}}</ref> The [[National Weather Service]] issues [[heat advisory|heat advisories]] and [[excessive heat warning]]s when it expects unusual periods of hot weather.

In Canada, heat waves are defined using the daily maximum and minimum temperatures, and in most of the country, the [[humidex]] as well, exceeding a regional threshold for two or more days. The threshold in which daily maximum temperatures must exceed ranges between {{convert|28|°C|°F}} in Newfoundland and {{convert|35|°C|°F}} in interior British Columbia, though this threshold is much lower in Nunavut, ranging between {{convert|22|°C|°F}} and {{convert|26|°C|°F}}.<ref>{{cite web |date=31 Jul 2024|title=Criteria for public weather alerts|url=https://www.canada.ca/en/environment-climate-change/services/types-weather-forecasts-use/public/criteria-alerts.html#heat|access-date=1 Feb 2025 |publisher=Environment and Climate Change Canada}}</ref>