Editing Philadelphia (section)

===Climate===
{{climate chart
| Philadelphia, Pennsylvania
|26.0|41.3|3.13
|27.5|44.3|2.75
|34.3|52.8|3.96
|44.3|64.7|3.47
|54.2|74.4|3.34
|63.9|83.2|4.04
|69.6|87.8|4.38
|67.9|85.8|4.29
|60.9|78.9|4.40
|49.2|67.2|3.47
|38.8|55.9|2.91
|31.2|46.0|3.97
|float=right
|clear=both
|units=imperial
}}
Within the [[Köppen climate classification]], Philadelphia falls under the northern periphery of the [[humid subtropical climate]] zone (Köppen ''Cfa'').<ref>{{cite web |url=http://www.weatherbase.com/weather/weather-summary.php3?s=80427&cityname=Philadelphia%2C+Pennsylvania%2C+United+States+of+America&units= |title=Climate Summary for Philadelphia, Pennsylvania |work=Weatherbase |access-date=September 17, 2014 |archive-date=June 28, 2014 |archive-url=https://web.archive.org/web/20140628232633/http://www.weatherbase.com/weather/weather-summary.php3?s=80427&cityname=Philadelphia%2C+Pennsylvania%2C+United+States+of+America&units= |url-status=live }}</ref> Within the [[Trewartha climate classification]], Philadelphia has a [[temperate]] [[maritime climate]] (''Do'') limited to the north by the [[continental climate]] (''Dc'').<ref>Trewartha GT, Horn LH (1980) Introduction to climate, 5th edn. McGraw Hill, New York, NY</ref> Summers are typically hot and muggy. Fall and spring are generally mild, and winter is moderately cold. The plant life [[hardiness zone#Selected U.S. cities|hardiness zones]] are 7a and 7b, reflecting an average annual extreme minimum temperature between {{convert|0|and|10|F|C}}.<ref>[http://planthardiness.ars.usda.gov/PHZMWeb/Images/All_states_halfzones_poster_300dpi.jpg "USDA Plant Hardiness Zone Map"] {{Webarchive |url=https://web.archive.org/web/20171121115552/http://planthardiness.ars.usda.gov/phzmweb/Images/All_states_halfzones_poster_300dpi.jpg |date=November 21, 2017 }}. ''usda.gov''. [[United States Department of Agriculture]]. Retrieved December 6, 2017. Note: high resolution map, may be slow to download.</ref>

Snowfall is highly variable. Some winters have only light snow while others include major snowstorms. The normal seasonal snowfall averages {{cvt|22.4|in|cm|0}}, with rare snowfalls in November or April, and rarely any sustained snow cover.<ref name="PhillyNOAA"/> Seasonal snowfall accumulation has ranged from trace amounts in 1972–73, to {{convert|78.7|in|cm|0}} in the winter of 2009–10.<ref name="PhillyNOAA"/>{{efn|See [[North American blizzard of 2009#Snowfall]] (December 19–20, 2009), [[February 5–6, 2010 North American blizzard#Snowfall]] (February 5–6, 2010), and [[February 9–10, 2010 North American blizzard#Impact]] (February 9–10, 2010). The February 2010 storms contributed to a single month record accumulation of {{cvt|51.5|in|cm|0}}. If no snow fell outside of February that season, 2009–10 would still rank as 5th-snowiest. See the Franklin Institute for a visual representation of seasonal snowfall.}} The city's [[North American blizzard of 1996#Philadelphia and Pennsylvania|heaviest single-storm snowfall]] was {{cvt|30.7|in|cm|0}}, which occurred in January 1996.<ref>{{Cite news |url=https://www.washingtonpost.com/blogs/capital-weather-gang/post/one-wild-storm-a-look-back-at-the-blizzard-of-96/2013/01/07/89a1242c-5875-11e2-9fa9-5fbdc9530eb9_blog.html |title=One wild storm: A look back at the 'Blizzard of '96' |last=Lipman |first=Don |date=January 7, 2013 |newspaper=Washington Post |language=en-US |access-date=December 19, 2017 |archive-date=December 19, 2017 |archive-url=https://web.archive.org/web/20171219085852/https://www.washingtonpost.com/blogs/capital-weather-gang/post/one-wild-storm-a-look-back-at-the-blizzard-of-96/2013/01/07/89a1242c-5875-11e2-9fa9-5fbdc9530eb9_blog.html |url-status=live }}</ref>

Precipitation is generally spread throughout the year, with eight to eleven wet days per month,<ref>{{cite web |url=http://www.met.utah.edu/jhorel/html/wx/climate/daysrain.html |title=Average Days of Precipitation, .01 Inches or more |access-date=July 28, 2006 |url-status=dead |archive-url=https://web.archive.org/web/20060620130836/http://www.met.utah.edu/jhorel/html/wx/climate/daysrain.html |archive-date=June 20, 2006 }}</ref> at an average annual rate of {{convert|44.1|in|mm|sigfig=3}}, but historically ranging from {{cvt|29.31|in|mm}} in 1922 to {{cvt|64.33|in|mm}} in 2011.<ref name="PhillyNOAA"/> The most rain recorded in one day occurred on July 28, 2013, when {{cvt|8.02|in|mm|0}} fell at [[Philadelphia International Airport]].<ref name="PhillyNOAA"/> Philadelphia has a moderately sunny climate with an average of 2,498 [[Sunshine duration|hours of sunshine]] annually. The percentage of sunshine ranges from 47% in December to 61% in June, July, and August.<ref name=noaasun-Phily1961/>

The January daily average temperature<!--NOT monthly normal high!--> is {{convert|33.7|°F|1}}. The temperature frequently rises to {{convert|50|°F}} during thaws. July averages {{convert|78.7|°F|1}}. Heat waves accompanied by high humidity and [[heat index|heat indices]] are frequent, with highs reaching or exceeding {{convert|90|°F|0}} on 30 days of the year. The average window for freezing temperatures is November 6 to April 2,<ref name="PhillyNOAA"/> allowing a growing season of 217 days. Early fall and late winter are generally dry, with February having the lowest average precipitation at {{convert|2.75|in|0}}. The dewpoint in the summer averages between {{convert|59.1|and|64.5|°F|0}}.<ref name="PhillyNOAA"/>

The highest recorded temperature was {{convert|106|°F|0}} on August 7, 1918. Temperatures at or above {{convert|100|°F|0}} are not common, with the last occurrence of such a temperature being July 21, 2019.<ref name="philadelphia1"/> The lowest officially recorded temperature was {{convert|-11|°F|0}} on February 9, 1934.<ref name="philadelphia1">{{cite web |url=http://www.stormfax.com/phlminmax2.html |title=Philadelphia Record Highs and Lows |access-date=April 3, 2007 |archive-date=March 22, 2007 |archive-url=https://web.archive.org/web/20070322192111/http://www.stormfax.com/phlminmax2.html |url-status=live }}</ref> Temperatures at or below {{convert|0|°F|0}} are rare, with the last such occurrence being [[1994 North American cold wave|January 19, 1994]].<ref name="PhillyNOAA"/> The record low maximum is {{convert|5|°F|0}} on February 10, 1899, and December 30, 1880. The record high minimum is {{convert|83|°F|0}} on July 23, 2011, and July 24, 2010.<ref>{{cite web |url=http://threadex.rcc-acis.org/ |title=Threaded Station Extremes |access-date=May 10, 2020 |quote=Station=PA – Philadelphia (Center City records are {{convert|12|°F|0}} on January 8, 2014, and January 19, 1997, for the record low maximum; and {{convert|87|°F|0}} on July 6, 1999, for the record high minimum) |archive-date=March 5, 2020 |archive-url=https://web.archive.org/web/20200305195121/http://threadex.rcc-acis.org/ |url-status=live }}</ref>

{{Philadelphia weatherbox}}