Snowfall Prediction Markets vs the National Weather Service: 10 Cities

By Arthur Angelo, PredictionScout Research · Updated Oct 23, 2026, 10:45 AM ET

Key findings

• 24 of 24 settled city-months match the NWS station total (Boston, Chicago, Detroit, Philadelphia, Seattle, Washington, D.C.; December 2025 to March 2026).
• At the start of each month, the side priced above 50¢ won 60 of 73 threshold contracts (82%); the market’s implied median missed the final total by a typical 3.3 inches across 9 months.
• December 2026 odds: in 4 of the 4 cities where the market median falls inside the listed thresholds, traders expect less snow than the 1991–2020 normal. Biggest gaps: Detroit 3.0 in vs an 8.9-inch normal; Boston 3.6 in vs a 9.0-inch normal; Minneapolis 7.8 in vs an 11.4-inch normal. Trading is thin: 129,121 contracts across all 10 cities so far.
• New settlement source. 10 of 10 open city markets now settle on The Weather Company’s snowfall dashboard; last winter’s markets named the NWS Daily Climate Report (CLI) for each airport. We keep checking against the NWS station record, so any gap between the two sources will show up here.
• Chicago had two December 2025 markets: one named Midway’s climate report and a second (“B”) event named O’Hare’s. Both are listed below.
• 26 ski resorts have opening-date markets for 2026/27; they settle on each resort’s announced first day of public skiing (ski opening dates).

December 2026 snowfall odds, city by city

Live prices from Kalshi (bid/ask midpoint, or the last trade when the spread is wide), as of the update time above. The market median is the snowfall total where the implied chance crosses 50%. In brackets: how often December snowfall at the same station topped that line in 1991–2020, from the NWS station record.

Last winter: every settled month vs the NWS record

Kalshi’s settlement value, or the range implied by which contracts paid out, against the monthly total at the station its rules named. A trace of snow counts as zero. The market median is taken from prices at 1 AM ET on the first day of the month.

Ski resort opening-date markets

Kalshi lists one market per resort asking when it will open for the 2026/27 season. Each contract is a date: “Before Nov 20, 2026” pays $1 if the resort opens to the public before that day. The contracts stack, so the chances should rise as the dates get later. We show the first date the market gives at least a 50% chance as the market’s middle.

How it settles. On the resort’s own announcement of its first day of public lift-served skiing, backed up by major news outlets. Season-pass holder previews and uphill-only days generally do not count; each market’s rules spell out the details.

What moves it. Early storms and, just as much, cold nights. Most large resorts open on man-made snow, so a run of nights below about 28°F for snowmaking can matter more than natural snowfall. Resorts that traditionally open on a fixed weekend (such as Thanksgiving) move less.

Worked example. If “Before Nov 20” trades at 45¢ and “Before Nov 27” at 80¢, the market sees roughly a 35% chance of an opening in the week of Nov 20 to Nov 26, and the middle is “before Nov 27”. If the resort announces an opening on Nov 22, the first contract pays $0 and the second pays $1.

For context we add the current snow depth at the nearest NRCS SNOTEL station (USDA Natural Resources Conservation Service automated sites, usually at high elevation). Snow depth at one station is a rough guide, not what the market settles on. Vermont has no SNOTEL sites, so eastern resorts show none.

Market middle: for “above X” ladders, the point where the implied chance crosses 50% (prices forced to fall as the threshold rises, interpolated between rungs). Prices are the bid/ask midpoint when the spread is 10¢ or less, otherwise the last trade. Events with fewer than 500 contracts traded show “thin trading” instead of a middle, and ladders whose quoted prices contradict each other show “prices out of order”. Pulled Oct 23, 2026, 10:44 AM ET.

Download the data

Settled city-months (CSV)Open markets vs climatology (CSV)Ski resort opening-date ladders (live) (CSV)

One row per settled city-month, and one row per open threshold contract with its live implied chance and the 1991–2020 base rate. No price histories are included. Free to reuse under CC BY 4.0 with a link back to this page.

Methodology

• Markets. Kalshi’s monthly snowfall series for Boston (KXBOSSNOWM), Chicago (KXCHISNOWM), Denver (KXDENSNOWM), Washington, D.C. (KXDCSNOWM), Philadelphia (KXPHILSNOWM), Seattle (KXSEASNOWM), Minneapolis (KXMSPSNOWM), Detroit (KXDETSNOWM), Pittsburgh (KXPITSNOWM), Milwaukee (KXMKESNOWM), each a ladder of “more than X inches” contracts, from Kalshi’s public API.
• Official data. Monthly snowfall totals and 1991–2020 normals for each airport station from the NWS/NOAA Regional Climate Centers’ Applied Climate Information System (the same station records behind the NWS Daily Climate Reports). Where a market’s rules named a different station (Chicago Midway for one December 2025 event), we use that station.
• Start-of-month price. Each contract’s price at 1 AM ET on the first day of the month (hourly-candle bid/ask midpoint, or last trade when the spread is wider than 10¢; 48-hour look-back). Prices are forced to fall as the threshold rises; the median is interpolated where the implied chance crosses 50%.
• Climatology. The share of Decembers from 1991 to 2020 with more snow than each threshold, at the same station. It is a base rate, not a forecast; it ignores this winter’s El Niño or La Niña signal and long-term trends.
• Limits. Live December prices come from thinly traded markets and can move sharply on a single trade; last winter is the only settled season for most cities, so the scored sample is small; snow totals are often revised in the days after a storm; The Weather Company’s data can differ from the NWS record, and this season’s markets settle on it. Nothing here is investment advice. Last run: Oct 23, 2026, 10:45 AM ET.

Data sources: prices and volumes come from the public APIs of Kalshi and Polymarket, with snowfall data from NOAA’s Regional Climate Centers (ACIS). All trademarks belong to their owners. PredictionScout is independent and not affiliated with any exchange. Nothing here is investment, betting, or legal advice.

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