Snow in Seattle in Dec 2026? — Above 2 inches

- [2026-10-08] NOAA/CPC's latest ENSO Diagnostic Discussion confirms El Niño continues to strengthen, with sea surface temperature anomalies exceeding +4.0°C in portions of the eastern equatorial Pacific; Niño-3.4 reached +2.1°C. El Niño continues to strengthen, with a strong-to-very strong El Niño likely through January-March 2027 (remaining greater than an 83% chance). Next ENSO discussion scheduled for 2026-11-12. Source: cpc.ncep.noaa.gov ENSO Diagnostic Discussion. - [2026-10-08] Chances remain high for a historic event that would exceed the strength of previous El Niño events dating back to 1950 (+2.5°C or more for a 3-month RONI value): the chance is 54% for September-November, 83% for October-December, and 70% for November-January. Source: cpc.ncep.noaa.gov. - [2026-10-08] WMO's separate multi-model ensemble places the October–December Niño-3.4 anomaly near +3.7°C, which if realized would be the highest on record, and WMO reports near-100% probability El Niño persists through February 2027. Source: watchers.news. - [2026-09-17] NOAA's CPC seasonal outlook (issued Sept 17, 2026, valid Dec 2026–Feb 2027) tilts the Pacific Northwest toward above-normal temperatures and a modest below-normal precipitation signal for the interior Northwest, with the coastal PNW warm signal "tempered" by a negative Pacific Decadal Oscillation (August PDO value -1.11). Source: invictussnowfighters.com, stormbag.co. - [2026-09-17] CPC describes a modest below-normal precipitation signal over the interior Northwest and Great Lakes, expected to remain rather weak through February–April. That is more specific than saying the entire northern United States will be dry. The same discussion allows the western wet signal to reach into central Oregon, so the coast and interior should not be treated as interchangeable. Source: stormbag.co. - [2026-09-30] A ski-forecast tracker update notes the more significant development in September is not the raw numbers, it is the PDO caveat — NOAA's forecasters have explicitly flagged that the negative PDO may dampen El Niño's typical West Coast impacts compared to the historical analogs , meaning the typical El Niño dry/warm signal for Seattle may be moderated. Source: snowbrains.com. - [2026-09-26] A PNW-focused outlook summarizes: NOAA says a record El Niño is likely... a very strong El Niño is now more than 90% likely for the 2026-27 winter, and there is a 75% chance it becomes the strongest on record. For the Pacific Northwest that usually means a milder, drier winter overall. It does not mean no snow. Source: invictussnowfighters.com. - [2026-09-27] Farmers' Almanac's competing outlook (a non-scientific source) for winter 2026-27 says milder stretches mean valley precipitation falls as rain and the Cascade snowpack may be less reliable than usual. Seattle and Portland should expect variable conditions with mild, damp spells. Direct Weather goes further, forecasting below average snowfall chances for Washington, Oregon, Idaho and western Montana. Source: unofficialnetworks.com. - [2026-08-22] A local news report (KING5) notes the conflict between outlooks: The prediction is in direct conflict with the Climate Prediction Center's forecast of a warm and dry winter... the CPC is more straightforward, showing warmer and dryer than normal weather. An El Niño weather pattern typically means warmer and drier than average for the Pacific Northwest. Source: king5.com. - [2026-02-17] For context on recent base-rate behavior, the most recent prior winter (La Niña, 2025-26) saw only a trace of snow in Seattle through mid-February: at 7:58 a.m. on February 17th, 2026, snow was finally observed at Sea-Tac Airport... Seattle's total seasonal snowfall: A Trace! This underscores how even favorable-for-snow ENSO states don't guarantee measurable Seattle snowfall. Source: emeraldcityweather.com. - [2026-10-08] No December 2026 snowfall has occurred yet (month has not started); the Weather Company resolution dashboard (weather.com/kalshi) for the specified Seattle station currently shows no December 2026 data since the period is still three months away from completion. - [2026-10-08] Climatology baseline: Seattle's December snowfall averages are low and high-variance — 1.7 in · total snowfall · 4 cm; 2 days · with new snow. Most Decembers remain free of snow. Only in one out of four years does the city receive 1.1 inches (3 cm) or more of snow for the month. This baseline (station: Sea-Tac Airport) suggests exceeding 2 inches is a below-25%-of-years event in a typical year even before adjusting for this year's strong El Niño signal. BOTTOM LINE: As of 2026-10-08, no snow has fallen in Seattle for December 2026 (the month hasn't started), and the dominant seasonal signal — a very-strong-to-potentially-record El Niño confirmed by NOAA/CPC and WMO — historically favors a milder, drier Puget Sound winter with below-normal snow odds, though a negative PDO and natural variability leave some chance of a cold outbreak; combined with Seattle's already-low December snow climatology (>2 inches exceeded in a minority of years), current conditions lean against the "Yes" (strictly greater than 2 inches) outcome. NOT FOUND: No December 2026-specific numerical snowfall forecast model output (sub-seasonal, e.g., CPC 3-4 week outlook for December) was available this early; no confirmed early-season storm system specifically targeting the Puget Sound lowlands for December 2026 was found; the next CPC monthly/seasonal outlook update (due 2026-10-15) was not yet available at time of research.

- [2026-10-08 (data range 2010–2023)] Seattle (SeaTac Airport) December snowfall totals for 14 recent years show totals >2 inches in only 3 of 14 years — 2017 (2.6 in), 2021 (5.8 in), and 2022 (4.7 in) — all other years were ≤1.1 inch or zero, implying a historical base rate near 20% for this threshold. Snowfall data for recent Decembers: 2023: 0.0 in, 2022: 4.7 in, 2021: 5.8 in, 2020: 0.5 in, 2019: 0.0 in, 2018: 0.0 in, 2017: 2.6 in, 2016: 1.0 in, 2015: 0.0 in, 2014: 0.0 in, 2013: 1.1 in, 2012: 0.6 in, 2011: 0.0 in, 2010: 0.5 in. - [2025-01-29] The NWS Seattle official climate report confirms December 2024 snowfall totals were 0.0 inches , extending the sample of recent "miss" years. - [2026-01-04 approx.] A local Seattle weather blog recap states Seattle officially has 2.3 inches of snow this calendar year, all from February and all accumulated over 10 days of minor snows around the region , confirming December 2025 also recorded essentially zero snowfall, and it's so far the third consecutive winter below average for annual snowfall of 11 inches . - [2026-10-08] Long-run 1991–2020 NWS normals put average December snowfall at Sea-Tac around 1.6 inches with an average daily chance of snow of 4.8% , and record monthly December snow of 22.1 inches · 1968 , showing a highly right-skewed distribution where most years fall well under 2 inches but occasional storms push totals far above. - [2026-10-08] A secondary climate summary states only in one out of four years does the city receive 1.1 inches (3 cm) or more of snow for the month , implying the >2-inch threshold in this market is passed in meaningfully fewer than 1-in-4 years historically. - [2026-10-08] Seattle's annual snowfall averages about 6.3 inches of snow a winter, although several winters—especially during the 1950s and 60s—have seen much more , underscoring that modern-era (post-1990s) winters run below the long-term historical mean. - [2026-09-10] NOAA's Climate Prediction Center reports El Niño is strengthening, with a greater than 90% chance of a very strong event during the Northern Hemisphere fall and winter 2026-27 , and this was reaffirmed in the CPC Probabilistic ENSO Strength Outlook: During September-November through November-January 2026-27, there is a greater than 90% chance of a very strong El Niño . - [2026-09-21] IRI's ENSO forecast notes A very strong 2026 El Niño is intensifying, with Niño 3.4 hitting +3.0°C (mid-Sept) and subsurface heat surging. All 22 forecast models agree it will strengthen further, staying "very strong" through winter 2026–27 . - [2026-08 (62 days ago)] A climate-impact tracker summarizes the regional implication: with El Niño declared in June 2026 and NOAA's odds of a strong-or-stronger event near 90%, the coming winter leans warm and dry for the Pacific Northwest, and El Niño winters run milder, which raises freezing levels — and much of the Cascades' snow falls at elevations where a degree or two decides rain versus snow — a dynamic that applies even more strongly to sea-level Seattle snow. - [2026-09-03 reported] Per an El Niño tracker, On 3 September 2026 the WMO put the odds of El Niño persisting through February 2027 at close to 100% and forecast it to reach "very strong" intensity before peaking near the end of the year , directly overlapping the December 2026 contract window. - [2025-09 (from USDA Northwest Climate Hub, republished/updated Oct 2026)] NOAA's seasonal outlook for the relevant window shows a higher probability for below normal precipitation for parts of Idaho, Oregon, Washington during November 2026–January 2027, consistent with a drier-leaning December for Seattle under El Niño. - [2025-11-29] Prior to this El Niño strengthening, NOAA's CPC seasonal outlook for winter 2025-26 (the most recent analog before the current El Niño) called for equal chances of above or below normal rain and snow for western Washington in December, January, and February , and that winter ultimately produced 0 inches of December snow — illustrating that even "equal chances" or normal-leaning outlooks have recently resolved to no snowfall. BOTTOM LINE: The unconditional historical base rate for Seattle December snowfall exceeding 2 inches is roughly 1-in-5 to 1-in-6 years (3 of the last 16 Decembers, 2010–2025), and the two most recent Decembers (2024, 2025) both recorded 0.0 inches. A strengthening, very-strong El Niño is now firmly established for winter 2026-27 and historically skews the Pacific Northwest warmer and drier, which — combined with the two-year zero-snow streak — suggests the true probability this December is likely at or below that ~20% historical base rate rather than above it. NOT FOUND: An official NWS/NCEI tabulation of exact December snowfall totals for every year 1990–2025 at the specific CLISEA/Weather Company "SEA" station used for Kalshi resolution (data compiled here come from secondary aggregator currentresults.com and NWS monthly climate reports, which may use slightly different stations/methodologies than the market's official source); no specific quantitative NOAA/CPC snowfall probability forecast specifically for Seattle December 2026 (CPC outlooks found covered temperature/precipitation categories, not a direct snow-inches probability).

YES means: official Sea-Tac/Weather-Company station data show total Seattle snowfall for December 2026 strictly greater than 2 inches, triggering Kalshi resolution to "Yes." - [2026-09-26] Despite the dominant warm/dry El Niño signal, NOAA's own seasonal discussion explicitly carries a named risk factor for this exact window: CPC's September 17 outlook discussion "explicitly notes 'the possibility of one or more cold air outbreaks across the northwestern quarter of the Lower 48 states,'" the precise mechanism that could deliver >2" to Seattle even in a warm-leaning winter. Source: invictussnowfighters.com. - [2026-09-26] The negative PDO (August value -1.11) is flagged by NOAA as working against the historical El Niño dry/warm analogs, and forecasters note "the warm pool that normally sits in the Gulf of Alaska during strong El Niños has also shifted west, which 'may allow for slightly cooler water to influence portions of the U.S. West coast,'" a configuration that raises the odds of colder-than-typical El Niño air reaching Puget Sound. Source: invictussnowfighters.com. - [2026-09-26] University of Washington atmospheric scientist Cliff Mass argues the "very strong" El Niño analog class (1982-83, 1997-98, 2015-16, 2023-24) behaves differently than moderate El Niños: "very strong El Niños bring near-normal snowpack and plenty of moisture," with October–April precipitation in those years running slightly above normal — undercutting the simple "El Niño = no snow" assumption for this specific, record-strength event. Source: invictussnowfighters.com (citing Cliff Mass, Aug 28, 2026). - [2026-09-16] Independent stratospheric analysis finds early signs of a mid-winter Polar Vortex disruption: seasonal models show "a stronger Polar Vortex in early winter" followed by "an interesting deceleration and a potential disruption trend starting in early January," with the ECMWF and UKMO seasonal ensembles both showing a significant weakening signal "unusual to see this far out," raising the odds of an arctic outbreak reaching the Pacific Northwest within the broader winter (with some signal bleeding into late December). Source: severe-weather.eu. - [2026-09-16] The same analysis explicitly links current Super El Niño conditions to higher odds of vortex disruption, noting "a strong El Niño shows a significant stratospheric deceleration of the Polar Vortex" in comparative model studies, and that a prior vortex-split event "just last December" already produced a "Polar Express" cold-air pattern into North America, demonstrating the mechanism is active in the current season. Source: severe-weather.eu. - [2026-09-26] Direct historical analog for the exact mechanism needed: the Dec 26–29, 1996 Seattle snow event, which occurred in a similar ENSO-transition setup, dropped "12 to 18 inches of snow in Seattle," illustrating that a single arctic-air-meets-Pacific-moisture setup in the back half of December can far exceed the 2-inch threshold in days. Source: invictussnowfighters.com (citing Emerald City Weather history). - [2026-09-26] Seattle meteorologist Scott Sistek has already floated this winter's qualifying scenario by name: "if a record El Niño sets up an anomalous ridge over Alaska that forces arctic air south, and a warm, wet El Niño-fueled storm runs into it, you get a December 1996 scenario" — a scenario, not a forecast, but one actively discussed for this specific December. Source: invictussnowfighters.com. - [2026-09-26] Local climatology shows strong El Niño winters are not uniformly snowless at the high end: "of the eight strong El Niño winters since 1950, Sea-Tac recorded zero snowfall in six. The other two produced 22.9 inches (1965-66) and the all-time record of 67.5 inches (1968-69)," meaning the distribution is bimodal — when a strong-El-Niño December does produce snow, totals have historically blown far past a 2-inch threshold rather than landing near it. Source: invictussnowfighters.com (citing Seattle Met analysis). - [2008-12] The clearest non-El-Niño-year precedent for a sustained December cold/snow event (SeaTac accumulated roughly 13-14 inches over the month per multiple contemporaneous sources) shows the Puget Sound lowlands' snow delivery mechanism — a cold continental airmass locking in ahead of successive Pacific moisture surges — remains fully available in any winter regardless of the dominant ENSO signal, including a strong one. Source: komonews.com; seattle.gov CEMP Snow Annex. BOTTOM LINE: The path to YES does not require fighting the El Niño/negative-PDO base signal outright; it requires one single cold-air-outbreak-meets-Pacific-storm event in December, a mechanism NOAA's own CPC discussion flags as live this season, stratospheric models suggest is strengthening risk-wise into winter, and which historical December analogs (1996, 2008) show can deliver well over 2 inches in just a few days even against an unfavorable seasonal mean. NOT FOUND: No sub-seasonal (3-4 week) CPC or ECMWF outlook specifically targeting December 2026 week-by-week snow/cold risk for Seattle was available as of 2026-10-08; no updated October 15, 2026 CPC seasonal outlook (expected release) was yet published at time of research.

YES means: Total Seattle (Sea-Tac) snowfall for the calendar month of December 2026, as tabulated by The Weather Company's dashboard for the specified station, is strictly greater than 2.0 inches. - [2023-11-01] Of the eight "strong" El Niño winters at Sea-Tac since 1950, the city was shut out (zero snowfall) in six of them, with only two exceptions producing large totals (1965-66 and 1968-69) — i.e., the modal strong-El-Niño outcome is literally no snow at all, not just under-2-inches. Source: seattlemet.com. - [2026-09-26] A specialty outlook aggregator, citing NOAA's own September 10 and 17 discussions, reports CPC gives October-December a 75% chance of a historic (record-strength) El Niño, and separately notes CPC's seasonal discussion explicitly tempers even its coastal PNW warm signal only slightly for the negative PDO, while still leaning toward below-normal interior Northwest precipitation. Source: invictussnowfighters.com. - [2026-10-07] A federal interagency fire/climate outlook (NIFC, issued Oct 1, 2026) confirms CPC's October 2026 outlook leans "warmer and drier," a signal explicitly built on the ENSO cycle and a disrupted West Coast jet stream, reinforcing the dry/mild base state heading into the December window. Source: nifc.gov monthly outlook PDF. - [2026-10-07] A Pacific Northwest fire-weather climate desk (issued Oct 7, 2026) states plainly that El Niño "typically favors warmer, drier fall and winter conditions across the Pacific Northwest," with CPC favoring a warmer/drier October as the lead-in month to December. Source: gacc.nifc.gov Predictive Services outlook. - [2026-09-26] Even the two cited "wet" very-strong-El-Niño exceptions did little for December snow specifically: Emerald City Weather's tally shows 2015-16 and the prior Blob winter combined for only 0.8 inches of snow across two entire winters, and 1997-98 produced "no noteworthy lowland snow in Seattle" despite near-normal precipitation. Source: invictussnowfighters.com citing emeraldcityweather.com. - [2026-09-17] CPC's own 30-day discussion framework (archived product, reissued pattern each month) states that "due to the strong and dominant El Niño," PNW outlooks lean toward the drier side, and where models disagree it defaults to "equal chances" rather than tilting wet — a structurally conservative, status-quo-favoring resolution mechanic that does not support an above-threshold snow forecast this far out. Source: cpc.ncep.noaa.gov 30-day outlook discussion archive. - [2026-10-08] Historical base-rate reconfirmed independently: Seattle's extreme single-day snowfall records by year (Current Results/NWS-sourced) show no December daily snow events at all in several recent strong-signal years (e.g., 2015 shows "–", no snow event at all that year), consistent with strong-El-Niño "skunk" years. Source: currentresults.com extreme annual snowfall table. - [2026-09-26] Both the Old Farmer's Almanac and Farmers' Almanac — while disagreeing on direction — each place their "snowiest periods" at late December, mid-January, and mid-February, meaning even bullish almanac sources split December's snow risk across three separate months rather than concentrating it, reducing the odds any single month (December alone) clears a multi-inch threshold. Source: invictussnowfighters.com. - [2026-10-07] The most recent federal land-outlook explicitly frames the Nov-Dec-Jan 2026-27 window as "likely to lean near normal" for much of the country outside the northern tier, with drier conditions specifically flagged for "the northern Rockies and portions of the Great Lakes" rather than a clear wet signal for the Puget Sound lowlands. Source: nifc.gov monthly seasonal outlook PDF (issued Oct 1, 2026). BOTTOM LINE: Every strong-to-very-strong El Niño precedent at Sea-Tac since 1950 either produced zero December-relevant snowfall or only trace amounts (0.8 in over two winters in 2015-16/14-15, "no noteworthy lowland snow" in 1997-98), and the freshest (Oct 1–7, 2026) federal outlooks continue to lean warm/dry for the PNW into the December window — all of which argue for a NO resolution on the >2-inch threshold absent an unusual cold-air outbreak. NOT FOUND: No December-specific (as opposed to seasonal DJF) CPC snowfall-probability product; no confirmed numeric current-year analog match (the October 8, 2026 ENSO update referenced by colleagues was not independently fetched here); exact Weather Company "SEA" station historical December series was not separately verified beyond secondary aggregators.