Snow in Philadelphia in Dec 2026? — Above 8 inches

- [2026-10-08] CPC ENSO Diagnostic Discussion: El Niño Advisory is in effect. Niño-3.4 was +2.1°C. A strong-to-very strong El Niño is likely through January–March 2027 (>83%). CPC gives an 83% chance of a historic event (3-month RONI ≥ +2.5°C) for Oct–Dec. 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 winter forecast expects below-average snow for the Northeast and Philadelphia. It calls for fewer measurable-snow days, but says big storms are still possible. It puts the main eastern storm risk in late January and February, not December. https://www.accuweather.com/en/press/2026-2027-united-states-winter-forecast/1943927 - [2026-10-08] Reports say AccuWeather forecasts 5–15 inches for Philadelphia for the whole 2026-27 season. That compares with a 23.1-inch normal and 30.1 inches last winter, per that report. https://www.fox29.com/news/snow-map-reveals-states-expected-see-most-snow-winter - [2026-10-01] Keystone Newsroom: CPC's outlook favors a milder-than-normal winter for much of PA and the Northeast. Its figure of "near 20 inches" for Philadelphia last season conflicts with AccuWeather's 30.1. https://keystonenewsroom.com/local/local-news/what-noaa-predicts-for-pa-snow-in-winter-2026-2027-forecast-released/ - [2026-10-01] Patch, citing CPC's DJF outlook: Philadelphia has a 40–50% chance of above-normal temperatures and a 40–50% chance of above-normal precipitation. The article notes that this could still bring extra snow if timing lines up. https://patch.com/pennsylvania/across-pa/new-map-predicts-2026-27-winter-forecast-what-it-means-pa-snow - [2026-09-11] The Weather Company's outlook (issued 2026-09-21 per the page) says winter will likely open warm in December, with much-above-average temperatures from the Central Appalachians into New England. The Weather Company also runs the resolution data source. https://weather.com/2026/09/11/news/weather/december-january-february-winter-outlook-is-in-see-who-gets-snow - Climatology, as of the 2025-11-28 CBS article: the 1991–2020 December normal at Philadelphia is 3.5 inches. December 2024 had 0.3 inches. https://www.cbsnews.com/philadelphia/news/philadelphia-snow-weather-winter-storms/ - Climatology, as of the 2025-12 PhillyVoice article: December snowfall reached a foot or more only twice since 1999 (24.1 inches in 2009, 12.7 inches in 2010). December 2020 had 6.6 inches. December 2021–2023 had only trace amounts. https://www.phillyvoice.com/winter-storm-philly-area-snowfall-december/ - Climatology: Dec 2013 had a large storm of 8.6 inches. A currentresults.com table shows that about one December in four exceeds 7 inches. https://www.currentresults.com/Weather/Pennsylvania/Places/philadelphia-snowfall-totals-snow-accumulation-averages.php - [2026-10-15] No December 2026 snow has fallen, since the month has not started. Nothing scheduled before 2027-01-01 other than the CPC outlook updates (the next ENSO discussion is 2026-11-12). No short-range forecast reaches December. The resolution source is the weather.com/kalshi dashboard, which I could not render or query for December 2026 data. BOTTOM LINE: Nothing has happened yet, and every seasonal signal (a record-strength El Niño, a warm December outlook, a below-normal AccuWeather seasonal forecast with storm risk centered on late January–February) points against a December total above 8 inches. The base rate is low: December totals above 8 inches have been rare (a handful of Decembers since 1999, e.g. 2009 and 2010). NOT FOUND: the current weather.com/kalshi station reading, any forecast for December 2026 specifically for Philadelphia, a month-by-month NOAA December snow outlook, and the sibling-strike or other-venue prices (not searched).

- [2026-10-07] AccuWeather's 2026-27 outlook expects a record-strength El Niño and below-average snow for the Northeast. It forecasts 5-15 inches for Philadelphia for the whole winter, after 30.1 inches last winter. It says the storm track is mainly southern early in winter. It warns that "it only takes one storm" and puts the main East Coast risk in late January and February. https://www.accuweather.com/en/winter-weather/winter-forecast-2026-2027-el-nino-to-reshape-snow-cold-in-us/1940765 - [2026-10-08] The Fox29 summary of AccuWeather says the same: 5-15 inches seasonal for Philadelphia, more rain, fewer measurable-snow days. https://www.fox29.com/news/snow-map-reveals-states-expected-see-most-snow-winter - [2026-08 to 2026-10] OpenSnow's winter preview favors below-normal snow for PA, MD and WV, with January and February snowier. It says the early and late season have a neutral to below-average signal. It also notes "boom or bust" potential for Philadelphia, DC and NYC in strong El Niño winters. https://opensnow.com/news/post/2026-2027-winter-forecast-preview - [2026-10-01] The NOAA CPC Dec-Feb outlook gives Philadelphia 40-50% odds of above-normal temperature and of above-normal precipitation, a classic strong-El Niño tilt. It gives no snowfall forecast. https://patch.com/pennsylvania/across-pa/new-map-predicts-2026-27-winter-forecast-what-it-means-pa-snow - [2026-10-15] Climatology, 1991-2020 normals at PHL: December averages 3.5 inches. The mean is skewed by rare big storms. One year in four exceeds about 7 inches, and about one in four has no snow. Days with at least 5 inches in December average 0.2 per year, and days with at least 10 inches average 0.1. Fetched page: https://www.currentresults.com/Weather/Pennsylvania/Places/philadelphia-snowfall-totals-snow-accumulation-averages.php - [2026-10-15] Historical December totals above 8 inches are rare. The largest are 27.0 inches in 1910 and about 24 inches in December 2009. The December 2009 storm brought 23.2 inches by Dec 20 (per Wikipedia). Other single days above 8 inches include 9.0 inches on 2000-12-30, 8.6 inches on 2013-12-08, and 12.4 inches on 1966-12-24. 10.9 inches fell on 1960-12-12. Past Decembers above 8 inches therefore include 1909, 1910, 1960, 1966, 2000 and 2009. 2002 had about 7 inches in one storm. 2013 and 2020 are near the threshold but need checking. Sources: https://www.extremeweatherwatch.com/cities/philadelphia/month-december and https://www.currentresults.com/Yearly-Weather/USA/PA/Philadelphia/extreme-annual-philadelphia-snowfall.php - [2026-01-15] Recent Decembers: December 2025 snowfall was about 1 inch above the 3.5-inch normal, so roughly 4.5 inches. The Dec 13-15, 2025 storm was the heaviest around Philadelphia since 2022. December 2024 had 0.3 inches. https://www.inquirer.com/weather/philadelphia-winter-2026-snow-forecast-20260115.html and https://www.cbsnews.com/philadelphia/news/philadelphia-snow-weather-winter-storms/ - [2026-10-15] Of Philadelphia's 10 biggest snowfalls, only three occurred before Jan 22. Peak snow season is late January to mid-February. https://www.inquirer.com/weather/philadelphia-winter-2026-snow-forecast-20260115.html - [2026-10-15] NWS Mount Holly cites a 55-year average of 21.6 inches a season. Weak El Niño winters averaged 28.1 inches, but there is no strong-El Niño December breakdown in the fetched material. https://www.weather.gov/media/phi/reports/analogs2005to2006.pdf - [2026-10-14] Kalshi lists December 2026 snowfall markets for other cities, such as Big Sky. No Philadelphia strike prices were found beyond this contract. https://www.foxweather.com/weather-news/big-sky-winter-early-snowfall-december-kalshi BOTTOM LINE: Roughly 5-8% of Decembers since the 1890s exceed 8 inches at Philadelphia, a rough tally from the records above and not a computed frequency. Most such months were driven by a single big storm. The strong-El Niño forecast (milder, southern storm track, below-normal snow, with snow risk skewed to January and February) points to the low end of that range. NOT FOUND: A complete year-by-year December snowfall series for PHL, and a computed exceedance frequency for more than 8 inches. The extremeweatherwatch monthly ranking page returned 403 when fetched. Strong-El Niño December analog snowfall for Philadelphia. Any Philadelphia-specific market quotes for other strikes.

YES means: Philadelphia's total December 2026 snowfall, as reported by The Weather Company's Kalshi dashboard, is strictly greater than 8.0 inches. - [2026-10-15] Most likely path to YES: a single high-end storm at or above the 2009 type, not an accumulation of small events. It needs a Gulf or Carolina low to track up the coast with cold air already in place. NWS Mount Holly recorded 23.2 in at PHL on Dec 19–20, 2009, the third-biggest single storm on record. Temperatures stayed in the 20s and the snow was fluffy. That one storm alone is nearly three times the 8-inch strike. It also came in a strong El Niño year, so the analog is relevant. https://www.weather.gov/phi/12192009wss - [2026-10-15] A strong El Niño does not rule out a big East Coast snowfall. Inquirer (2023) says that four of seven strong-El Niño winters were snowy, with 20-inch-plus storms in 2009-10 and 2015-16. The other three were snow-starved. The 2009-10 season was Philadelphia's snowiest on record, at 78.7 inches. Outcomes are bimodal ("all or nothing"), which fattens the tail relative to a simple "mild" read. https://www.inquirer.com/weather/el-nino-snow-philadelphia-winter-prediction-20230925.html - [2026-10-15] Weather.com's Todd Crawford (2023) said the atmosphere then resembled 2009-10. Weatherbell's Bastardi said a 2009-style December was possible. This shows forecasters have treated an early big storm as a real strong-El Niño possibility, though the 2023 outcome is not checked here. https://www.inquirer.com/weather/philadelphia-winter-weather-forecast-snow-el-nino-20231019.html - [2026-09-21] Severe Weather Europe's ECMWF seasonal run (page updated 2026-09-21) shows increased December snowfall potential across the central Plains and "toward the northeastern U.S." That is the only model-based December signal for the East that I found leaning wetter or snowier. The UKMO run on the same page shows below-normal Northeast snow in December. Treat it as a weak, model-dependent signal. https://www.severe-weather.eu/long-range-2/winter-2026-2027-seasonal-models-first-snowfall-predictions-super-el-nino-united-states-canada-europe-fa/ - [2026-09-21] The same page shows a strong El Niño pressure setup: a blocking high over Canada and a deep low across the southern and eastern U.S. It says this pattern can raise snow potential "if enough cold air is available." The path to YES therefore needs a cold-air source, such as Greenland blocking. Newsweek (about 2026-10-09) cites AccuWeather saying that blocking near Greenland plus cold air would raise Mid-Atlantic snow chances. https://www.newsweek.com/el-nino-snow-map-shows-states-facing-biggest-winter-shift-12535115 - [2026-10-09] AccuWeather says the number of heavier snow events in Philadelphia and NYC may stay near historical levels even with fewer measurable-snow days. Snowfall is concentrated in a few events, which is what a YES needs. https://www.newsweek.com/el-nino-snow-map-shows-states-facing-biggest-winter-shift-12535115 - [2026-10-07] AccuWeather's 5–15 inch seasonal range for Philadelphia has an upper end of 15 inches. A December of 8+ inches would be over half of that upper bound, so it needs a major early storm. Pastelok warns "it only takes one storm to flip the script". AccuWeather's emphasis, though, is on late January and February. https://www.accuweather.com/en/winter-weather/winter-forecast-2026-2027-el-nino-to-reshape-snow-cold-in-us/1940765 - [2026-01-15] Recent history shows December can deliver snow. December 2025 was 3.6°F below normal at PHL and about 1 inch above the snowfall average (4.8 in with January's 0.3 in). The Dec 13–15, 2025 storm was the heaviest around Philadelphia since 2022. It shows a cold-air arctic-front setup can produce a notable event, but it fell well short of 8 inches. https://www.inquirer.com/weather/philadelphia-winter-2026-snow-forecast-20260115.html - [2026-10-15] Timing: Philadelphia's median first measurable snow is Dec 18, so most of the month's snow is compressed into its second half. A mid-to-late December storm, as in 2009, would be inside the window. https://mywild.report/winter-forecast-pennsylvania - [2026-10-15] The resolution mechanics are not a hurdle in either direction. The rule is strictly more than 8 inches, summed over local calendar days. That total is cumulative across storms, so 2 or 3 moderate events of about 3–4 inches each could also reach it. NWS Mount Holly's 1971–2000 days of 1 inch or more average 0.5 per December at PHL. That gives a rough sense of how few such days there are. https://www.weather.gov/media/phi/reports/snowfalltables.pdf BOTTOM LINE: YES needs one December coastal storm like Dec 2009 (cold air plus a southern-stream low), or a cold-air outbreak with several moderate snow events. Strong El Niño years are bimodal and storms of that size have happened in this setup, but the seasonal outlooks all lean against it. NOT FOUND: Any model or forecaster call that specifically favors a snowy Philadelphia December 2026. A strong-El Niño December-only snowfall series for PHL. Current weather.com/kalshi data. Live Philadelphia strike prices. A complete count of Decembers with more than 8 inches.

YES means: Philadelphia's total snowfall for December 2026 (Dec 1–31 local days) is strictly greater than 8.0 inches in the Weather Company/Kalshi dashboard data. - [2026-09-11] The Weather Company outlook, fetched in full, is the same company that supplies the resolution data. It expects early-season Northeast storms to be "mostly rain and little snow". It is confident December opens warm, with much-above-average temperatures from the Central Appalachians into New England. Its January map keeps the northern half above average. Its cold, favorable-track signal for the Northeast arrives only in February. Every month-by-month signal for the Northeast puts the snow risk after December. https://weather.com/2026/09/11/news/weather/december-january-february-winter-outlook-is-in-see-who-gets-snow - [2026-10-?? (read 2026-10-15)] OpenSnow's analog work, per the search snippet, puts December among the stronger below-average snow months for the region in strong El Niño winters. It puts the neutral-to-above signal in January and February instead. This is a month-specific December signal that the earlier reports' general "below-normal season" language lacks. https://opensnow.com/news/post/2026-2027-winter-forecast-preview - [2026-10-15] Daily-record table from currentresults.com (search result): Philadelphia's biggest single-day December snowfall in recent decades was above 8 inches only in 2000 (9.0 inches on Dec 30) and 2009 (22.5 inches on Dec 19). Dec 2013 reached 8.6 inches in one day. Dec 2002 (7.0) and Dec 2020 (6.3) fell short. A month above 8 inches generally needs a single major storm, since 2–4 inch events don't add up to 8. The recent single-storm peaks that missed the threshold show how often a "big" December storm still lands under 8. https://www.currentresults.com/Yearly-Weather/USA/PA/Philadelphia/extreme-annual-philadelphia-snowfall.php - [2026-10-15] Strong El Niño precedent: Dec 2009 was the lone strong-El Niño December with a big storm, and it was an outlier. The 2023 Inquirer piece said the 2023-24 strong El Niño was "all or nothing". Weather.com's own strong-El Niño analysis said such events can be "significant snow erasers" in the north. In 2023-24, forecasters called for a mild December and a cooldown later, and the strong-El Niño season delivered 11.2 inches for the whole winter (extremeweatherwatch). A strong El Niño can't be assumed to bring December snow, and the 1972-73 strong-El Niño season produced no measurable snow at all. https://www.inquirer.com/weather/philadelphia-winter-weather-forecast-snow-el-nino-20231019.html ; https://www.extremeweatherwatch.com/cities/philadelphia/snowiest-winter-season - [2026-10-14] AccuWeather/Newsweek: warmth in the Northeast is expected to "delay winter's arrival". Philadelphia is expected to see fewer measurable-snow days. The heavy-event count could stay near historical levels. The only route to Yes is therefore one or two rare large events landing in a month that is expected to be warm. https://www.newsweek.com/el-nino-snow-map-shows-states-facing-biggest-winter-shift-12535115 - [2026-10-09] The CPC Week 3-4 discussion says El Niño teleconnections will likely keep influencing the US into November. The Aug 20 CPC update (Unofficial Networks) put the strongest warm signal over the Northeast. The December-specific CPC outlook is not due until Oct 15–Nov 19 releases, so no source yet backs a cold December. https://www.cpc.ncep.noaa.gov/products/predictions/WK34/ ; https://unofficialnetworks.com/2026/08/20/noaa-updated-winter-weather-prediction/ - [2026-09-08] Resolution technicalities, per Turbine's reading of Kalshi's rulebooks. Snow contracts built on NWS NOWData count a trace ("T") as 0.00 and a missing day ("M") as 0.00. Resolution locks to the value displayed at expiration, so later corrections don't count. A missing or incomplete daily report can only lower the total, which can only push toward No. This contract's own rules point to the weather.com/kalshi dashboard, and the same source says the rulebook text is sometimes stale versus the live rules. I could not confirm which source this contract uses. https://www.turbinefi.com/blog/how-to-trade-kalshi-weather-markets-2026 - [2026-09-08] Station: Philadelphia settlement is tied to Philadelphia International Airport (KPHL/CLIPHL) per the same source and Wethr's guide. The airport sits at 36 ft elevation in the Coastal Plain, southwest of the city. Airport sites often read less snow than the inland and northwest suburbs in marginal-temperature events, which matters for rain-snow-line storms. Not verified against recorded differences. https://wethr.net/edu/market/philadelphia - [2026-10-15] Using extremeweatherwatch's annual and seasonal totals, many strong seasons had a modest December: 2013 was 19.1 inches for the calendar year and 8.3 for 2012-13, and Dec 2020 was 6.6 inches within a 23.9-inch season. This shows that even snowy years often fall short of 8 inches in December alone. Snow in the typical season is concentrated in Jan–Feb. https://www.extremeweatherwatch.com/cities/philadelphia/snowiest-winter-season - [2026-10-15] Status quo and timing: December is the only month that counts. A big late-December storm is allowed, but the window closes Dec 31. Nothing has accrued, no forecast reaches December, and any Yes requires a roughly one-in-20 event under climatology plus a warm-tilted seasonal setup. A single cold week would not be enough. BOTTOM LINE: The warm December signal from the resolver's own parent company, a record El Niño, and the late-winter timing of storm risk all point to a total well under 8 inches. A Yes needs a rare single-storm outlier, as in 2009 or 2000, and missing or trace data can only reduce the total. NOT FOUND: A complete year-by-year December monthly snowfall series for PHL, a December-specific NWS or CPC snow outlook, the live weather.com/kalshi data, and confirmation of whether this contract settles on NWS or Weather Company data.