Snow in Philadelphia in Dec 2026? — Above 2 inches

- [2026-12-01 onward] December 2026 has not started. No December snow has fallen, and there is nothing yet on the resolution source (weather.com/kalshi). I did not open that dashboard. Source: https://weather.com/kalshi - [2026-10-08] CPC ENSO discussion: El Niño Advisory is in effect. Niño-3.4 is +2.1°C. A strong-to-very-strong event is likely through Jan–Mar 2027 (more than 83% chance). The chance of a historic event (3-month RONI of +2.5°C or more) is 83% for Oct–Dec and 70% for Nov–Jan. CPC says El Niño impacts are more likely but not guaranteed. The next update is 2026-11-12. https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml - [2026-10-07] AccuWeather's 2026-27 outlook (reported by FOX 29) puts Philadelphia at 5–15 inches for the season. Last winter it measured 30.1 inches. The outlook expects a mild, rainy early winter with little early-season snow in the East. Its main snowstorm risk is late January and February. https://www.fox29.com/news/snow-map-reveals-states-expected-see-most-snow-winter - [2026-10-07] AccuWeather's chart compares its 5–15 inch forecast with a Philadelphia seasonal normal of 23.1 inches. https://dailyvoice.com/article/brand-new-winter-snow-predictions-released-where-totals-could-stack-up/ - [2026-10-01] NOAA CPC's Dec–Feb outlook gives Philadelphia a 40–50% chance of above-normal temperature and a 40–50% chance of above-normal precipitation. Patch reports it as a classic strong El Niño pattern. https://patch.com/pennsylvania/across-pa/new-map-predicts-2026-27-winter-forecast-what-it-means-pa-snow - [2026-10-01] The Keystone Newsroom headline says the CPC outlook favors a milder-than-normal winter across Pennsylvania and the Northeast. https://keystonenewsroom.com/local/local-news/what-noaa-predicts-for-pa-snow-in-winter-2026-2027-forecast-released/ - [Climatology, 1991–2020 normals] The PHL December snow normal is 3.5 inches. Source: https://www.cbsnews.com/philadelphia/news/philadelphia-snow-weather-winter-storms/ - [Climatology, as of Nov 2025] The NWS reported under 1 inch in each of the four previous Decembers: 2021–2023 trace, 2024 0.3 inches. 2020 had 6.6 inches. Since 1999 only two Decembers reached a foot or more: 2009 with 24.1 inches and 2010 with 12.7 inches. December 2025's total was not found. https://www.phillyvoice.com/winter-storm-philly-area-snowfall-december/ - [Climatology] One site says one year in four exceeds 7 inches in December and one in four has none. It says 3 inches or more occurs about once every 3 years, and 5 inches or more about once every 5 years. These are third-party estimates. https://www.currentresults.com/Weather/Pennsylvania/Places/philadelphia-snowfall-totals-snow-accumulation-averages.php and https://freetoursbyfoot.com/philadelphia-weather-december/ - [2026-10-14] Old Farmer's Almanac outlook for the Atlantic Corridor: winter snowfall slightly below normal, with early-to-mid December among the coldest periods. The page appears old (about 723 days). Low reliability. https://www.almanac.com/weather/longrange/pa/philadelphia BOTTOM LINE: Nothing has happened yet, and seasonal signals lean mild: a record-strength El Niño and AccuWeather's below-normal snow outlook, with the storm risk placed in late winter. Against that, the December normal is 3.5 inches, but recent Decembers were mostly under 1 inch, so more than 2 inches depends on one event. NOT FOUND: Any current weather.com/kalshi reading for PHL. A CPC December-specific snow outlook. Any 2-week or sub-seasonal December forecast, which is too early to exist. December 2025's PHL snowfall total.

- [2026-10-14] Climatology: Philadelphia's 1991–2020 December snowfall normal is 3.5 in. The same page says one December in four exceeds 7 in and one in four has no snow. Days with at least 3 in of snowfall average 0.3 in December. The mean is skewed by rare big storms, so the median is lower. https://www.currentresults.com/Weather/Pennsylvania/Places/philadelphia-snowfall-totals-snow-accumulation-averages.php - [2026-10-14] The 2010–2019 December average was 3.4 in. The same page gives roughly 0.7 days a month with at least 1 in in December (1991–2020 normals). https://www.currentresults.com/Weather/Pennsylvania/Places/philadelphia-snowfall-totals-snow-accumulation-averages.php - [2026-01-15] Recent Decembers: December 2025 snowfall was about 1 in above average (so about 4.5 in, using the 3.5 in normal; this is my inference). The Dec 13–15, 2025 storm gave the heaviest snow in the area since 2022. The Inquirer gives the season total to Jan 15 as 4.8 in, with 0.3 in in January. https://www.inquirer.com/weather/philadelphia-winter-2026-snow-forecast-20260115.html - [2025-11-28] December 2024 snowfall was only 0.3 in, per CBS Philadelphia, which put the 2024–25 season total at 8.1 in. A year-by-year December series for Philadelphia was not retrieved. https://www.cbsnews.com/philadelphia/news/philadelphia-snow-weather-winter-storms/ - [2026-10-14] Tail history: December daily records include 22.5–23.2 in (Dec 2009), 8.6 in (Dec 2013) and 6.3 in (Dec 2020). Single big storms are what push December past 2 in. https://www.currentresults.com/Yearly-Weather/USA/PA/Philadelphia/extreme-annual-philadelphia-snowfall.php - [2026-10-07] AccuWeather's 2026-27 outlook expects a possibly record-strength El Niño. It forecasts 5–15 in of snow for Philadelphia for the whole winter, against 30.1 in last winter. It also says the primary storm track will sit across the southern US early in winter, so many eastern areas will likely see very little early-season snow. https://www.fox29.com/news/snow-map-reveals-states-expected-see-most-snow-winter - [2026-08-11] OpenSnow: the El Niño snow signal is strongest in January–February, with a neutral to below-average signal for early and late season. It describes Mid-Atlantic coastal cities including Philadelphia as "boom or bust" in strong El Niño winters. https://opensnow.com/news/post/2026-2027-winter-forecast-preview - [2026-10-01] NOAA CPC's Dec–Feb outlook (reported by Patch, about 2026-09-30) gives Philadelphia 40–50% odds of above-normal temperature and 40–50% odds of above-normal precipitation. CPC does not forecast snowfall totals. https://patch.com/pennsylvania/across-pa/new-map-predicts-2026-27-winter-forecast-what-it-means-pa-snow - [2026-09-08] The Old Farmer's Almanac calls for above-average temperatures and slightly below-normal snowfall in the Philadelphia area. It has little verified skill. https://northeasttimes.com/2026/09/08/philadelphia-area-faces-milder-winter-but-snow-chances-remain-through-march/ - [2026-10-14] Typical first measurable snow in Philadelphia is around Dec 18 (range Nov 25–Jan 15), per mywild.report. A local radio station's 18-year first-trace analysis gives an average first-snow date of Nov 23. Seasonal-forecast skill for snowfall totals is described as essentially nil. https://mywild.report/winter-forecast-pennsylvania - [2026-10-14] A Kalshi December 2026 snowfall market exists for Big Sky, which shows the series runs. I found no outside odds for Philadelphia. The Big Sky odds were reported by Fox Weather. https://www.foxweather.com/weather-news/big-sky-winter-early-snowfall-december-kalshi - [2026-10-14] Resolution detail: the market uses The Weather Company's station data, not NWS, so totals may differ slightly from NWS figures. Trace amounts count as zero. BOTTOM LINE: The 3.5 in December mean sits above a lower median. The statistics imply roughly 35–45% of Decembers exceed 2 in, which is my estimate from the quartile data and not a sourced figure. Because the strong El Niño favors a warm early winter with a southern storm track, the outlook tilts this below climatology. NOT FOUND: a year-by-year NWS or NOWData December snowfall table for Philadelphia, so the exceedance frequency is only approximated. I also found no CPC final winter outlook (due Oct 15) and no Philadelphia-specific Kalshi or other market odds.

YES means: Philadelphia's total December 2026 snowfall on the Weather Company (weather.com/kalshi) station data is strictly greater than 2.0 inches. Trace amounts do not count. - [2026-09-11] The Weather Company's own outlook (the same company that supplies the resolution data) favors a stormier East Coast pattern. That raises the number of precipitation events in play, and the YES case needs only one cold-enough event. Its caveat is that cold air is lacking early, so much of that precipitation may fall as rain. It also expects a warm December. https://weather.com/2026/09/11/news/weather/december-january-february-winter-outlook-is-in-see-who-gets-snow - [2026-10-12] Newsweek reports AccuWeather expects fewer measurable-snow days in Philadelphia and NYC but heavier-snow events near historical levels. It adds that Greenland blocking plus enough cold air would raise Mid-Atlantic snow prospects. That supports a "few days, one big storm" path to YES. https://www.newsweek.com/el-nino-snow-map-shows-states-facing-biggest-winter-shift-12535115 - [2023-11-30] Weather.com analysis of nine strong El Niños since 1950: Philadelphia and DC averaged markedly more snow in strong El Niño winters. NYC and Boston were not that way. Winters with frequent Greenland blocking were much snowier. Only three such winters exist in the record, and 2009-10 skews them. Strong El Niños without blocking were far less snowy along I-95. So YES prerequisite = a negative-NAO/Greenland block. https://weather.com/storms/winter/news/2023-11-29-el-nino-snow-northeast-us - [2023-09-25] The Inquirer, citing CPC's L'Heureux: Philadelphia is "on the bubble" in strong El Niños. Four of seven strong El Niño winters were snowy, with 20-inch-plus storms in 2009-10 and 2015-16. https://www.inquirer.com/weather/el-nino-snow-philadelphia-winter-prediction-20230925.html - [2009-12-19] The best analog is December 2009, a strong El Niño. Philadelphia got 23.2 inches on Dec 19-20 in one storm, which alone is more than 11 times the threshold. https://www.fox29.com/weather/what-were-biggest-snowstorms-philadelphia-area-history - [2025-12-15] Recent proof that one storm suffices. The Dec 14, 2025 storm gave 4.2 inches at PHL airport, enough alone to clear 2 inches. It fell with temperatures near freezing. Marginal-temperature events can still deliver. https://www.inquirer.com/weather/snow-how-much-philadelphia-weather-20251215.html - [2025-12-27] Another December 2025 event, Dec 26-27, was forecast at 1.5–4 inches for Philadelphia, with NWS giving PHL about 30% for 4 inches or more. It ended up only a few tenths in the city (a mix). Late-December events can add to an earlier total. https://www.fox29.com/news/philadelphia-snow-forecast-totals-dec-26-2025 and https://www.fox29.com/news/snow-totals-how-much-fell-around-philadelphia-overnight-saturday - [2000-12-30] A strong December nor'easter hit Philadelphia with 10 inches. The month is not limited to early cold. Wikipedia shows these occur even when DC and Baltimore get little. https://en.wikipedia.org/wiki/December_2000_nor%27easter - [2026-09-?? via Wikipedia/SevereWeather] Severe-weather.eu notes the ECMWF December snowfall forecast shows increased potential toward the east and northeastern US. It also notes UKMO shows below-normal snow in the Northeast. Models disagree. https://www.severe-weather.eu/long-range-2/winter-2026-2027-seasonal-models-first-snowfall-predictions-super-el-nino-united-states-canada-europe-fa/ - [2026-09-30 approx.] The Yahoo/Newsweek-style NOAA piece highlights above-normal precipitation along the East Coast for Dec-Feb. More wet days means more shots at the cold-side of a storm. https://www.yahoo.com/news/weather-news/articles/noaa-predicts-snowy-winter-northeast-191900915.html - [2026-10-14] The Old Farmer's Almanac's current outlook (an unreliable source) lists early-to-mid December among the coldest periods for the Atlantic Corridor, with Philadelphia's region slightly below normal on snow. For the Northeast's southern part it lists mid/late December as snowiest. Low skill. https://www.almanac.com/winter-extended-forecast-farmers-almanac BOTTOM LINE: The most likely path to YES is one coastal low in the active El Niño southern/East Coast storm track, which meets a temporary cold shot from a Greenland block or negative NAO. It needs only about 2 inches at PHL, and a single event did that in Dec 2025 (4.2 inches). The Weather Company's warm-December call and its warning of rain-dominant early storms are the main obstacles to this argument. NOT FOUND: Philadelphia's year-by-year December snowfall series, any December-specific CPC snow outlook, and any current weather.com/kalshi reading.

YES means: Philadelphia's total December 2026 snowfall, as reported on The Weather Company's weather.com/kalshi dashboard, is strictly greater than 2.0 inches. - [2026-07-10] An Inquirer piece, which I fetched, lists the strongest El Niño winters in Philadelphia. The winters of 1991-92 and 1997-98 were nearly snowless, and 1972-73 was the only truly snowless winter on record. In 1965-66 no snow fell until the end of January. Its conclusion: "Expect anything." The pattern supports a late-start, late-winter case, not a December one. https://www.inquirer.com/weather/el-nino-philadelphia-weather-atlantic-hurricanes-snow-20260710.html - [2023-09-25] NOAA's Michelle L'Heureux said Philadelphia is "right on the bubble" in strong El Niños. Four of seven strong-El Niño winters were snowy. The big events named were late-season ones (Feb 1983, Feb 2010, Jan 2016) plus Dec 9-10, 2009. In the NO years the whole winter failed, and December is the least reliable month. https://www.inquirer.com/weather/el-nino-snow-philadelphia-winter-prediction-20230925.html - [2020-02-12] The Inquirer's list of snow-deprived winters includes 1997-98, a record El Niño, at only 0.8 in. It says warm air flooded North America and snow avoided Philadelphia despite a sequence of potent nor'easters. This is the closest analogue to a record-strength event, and it produced a NO-type outcome even with active storms. https://www.inquirer.com/weather/snow-philadelphia-winter-record-climate-change-20200212.html - [2026-09-17] The CPC seasonal outlook, read through a Sept 17 summary, leans above-normal for temperature across the Northeast for Oct–Dec and Dec–Feb, with a wet signal along the Atlantic coast. Warm and wet in December favors rain. https://homealmanac.us/outlook/northeast/ - [2026-09-17] Unofficial Networks reports that NOAA puts odds above 90% on a very strong event through mid-winter. It describes the Northeast as "wetter but warmer," which means storm-by-storm outcomes. A CPC outlook is not a snowfall forecast. https://unofficialnetworks.com/noaa-2026-winter-weather-forecast/ - [Undated Inquirer climatology piece] About 90% of December precipitation in Philadelphia falls as rain. Big snows need coastal storms, and Atlantic water in the low 40s tends to import mild air on onshore winds. A December total above 2 in therefore usually needs one rare, well-timed storm. https://www.inquirer.com/philly/blogs/weather/Ultra-White-Christmas.html - [Climatology, record tables] Most Decembers with big totals came from a single storm: Dec 2009 (22.5 in), Dec 2000 (9.0), Dec 2002 (7.0), Dec 2013 (8.6) and Dec 2020 (6.3). Many Decembers in that table had no large daily total. The currentresults page gives only about 0.7 days per December with at least 1 in, and 0.3 days with at least 3 in. Reaching more than 2 in usually means one event or a rare run of small events. https://www.currentresults.com/Yearly-Weather/USA/PA/Philadelphia/extreme-annual-philadelphia-snowfall.php - [2026-10-14, resolution mechanics] The rules say to use initial non-preliminary values from The Weather Company, with trace counted as zero and missing days adding nothing. The threshold is "strictly greater than 2". Exactly 2.0 in resolves NO. Daily trace and sub-0.1 in amounts never accumulate. Under Kalshi's sister NOWData snow contract, a total of exactly the threshold does not count for "above". Post-expiry corrections are ignored. That contract names NWS NOWData as its source, while this one names The Weather Company. The Weather Company's data feed is newer and its snowfall treatment is less tested. https://kalshi-public-docs.s3.amazonaws.com/contract_terms/NOWDATASNOW.pdf - [2026-09/10] One third-party trading guide, dated about 2026-09, says Kalshi precipitation and snow contracts still settle on NWS climate reports. This conflicts with this contract's weather.com/kalshi wording. The source mismatch is a minor risk, and it may favor NO if data are missing or incomplete. Total tends to be undercounted when days are missing. https://www.turbinefi.com/blog/how-to-trade-kalshi-weather-markets-2026 - [2025-11 PhillyVoice] Four straight Decembers before 2025 stayed under 1 in (2021–23 trace, 2024 0.3 in). The 2020 total of 6.6 in was the only one over 2 in in the five Decembers from 2020 to 2024. The recent run supports status-quo NO. https://www.phillyvoice.com/winter-storm-philly-area-snowfall-december/ - [2026-10-14] Two days ago, CPC's 8-14 day tables show warmth across the interior and south in late October. That is too early to say anything about December. There is no sub-seasonal signal for December yet, so the status quo, no snow on the ground, stays. https://www.cpc.ncep.noaa.gov/products/predictions/610day/fxus06.html BOTTOM LINE: The strongest NO case is that a record-strength El Niño, a warm-and-wet CPC tilt, and a storm track that favors late winter all point against December snow, with 1997-98 as the analogue. The strict "greater than 2.0" threshold, trace counted as zero, and the need for one well-timed storm in a month where about 90% of precipitation is rain also favor NO. NOT FOUND: A year-by-year December snowfall table for Philadelphia. Any current weather.com/kalshi reading. A CPC December-specific outlook. A statistical study of December snow in strong El Niño Decembers for Philadelphia. Any Philadelphia-specific Kalshi odds, which I did not look for.