Polymarket vs. Kalshi
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See where the two biggest prediction markets disagree. Pick any two markets, or start from the biggest gaps below: prices, volume, history and the resolution rules, side by side.
Will Waymo operate ride-hailing in St. Louis, MO before Jan 1, 2028?
Vol $0 today · $0 total
Kalshi is 53 points higher than Polymarket (54% vs 1%). They resolve on different dates (Oct 20 vs Dec 31), so they may not be exactly the same bet.
History starts when we first saw each market, so a newly added market has a short line.
| Polymarket | Kalshi | |
|---|---|---|
| Probability (Yes) | 1% | 54% |
| Change (24h) | +0.0 pt | +18.5 pt |
| Volume today | $0 | $0 |
| Total volume | $0 | $0 |
| Liquidity | $1.1K | — |
| Open interest | — | — |
| Resolves | — | 15mo |
| Tracked for | 3 days | 3 days |
Resolution rules: read both before trusting a gap
Polymarket
This market will resolve to "Yes" if St. Louis, MO falls within a tornado probability area rated ≥2% in the NOAA Storm Prediction Center Day 1 Convective Outlook on October 19, 2026. Otherwise, this market will resolve to "No". The SPC Day 1 Convective Outlook assigns tornado probability percentages (2%, 5%, 10%, etc.) to geographic areas across the US. If the city's coordinates fall inside any area rated 2% or higher, that city resolves "Yes". If a city is outside all tornado probability areas, or only within areas rated below 2%, that city resolves "No". The SPC outlook is published as machine-readable geographic data (GeoJSON) at spc.noaa.gov. Each city's coordinates and the polygon boundaries are publicly verifiable. Borderline cases can be independently confirmed using the polygon data (excluding the hatched SIGN overlay, which is not a probability rating) and the city's listed coordinates. The point-in-polygon test is performed on unprojected WGS84 (EPSG:4326) coordinates, which is the native coordinate system of the SPC GeoJSON data. Resolution is based on the scheduled 01:00 UTC Day 1 Convective Outlook update issued on the following UTC calendar day. The SPC Day 1 outlook covers a 24-hour period from 12:00 UTC to 12:00 UTC the following day. That scheduled update is the revisions cutoff; subsequent revisions published after it will not be considered. If the SPC Day…
Kalshi
If Waymo is operating commercial autonomous vehicle ride-hailing services available to the general public within St. Louis, MO before Jan 1, 2028, then the market resolves to Yes.
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Informational only — not financial advice. Odds are mirrored from each platform and may lag the live order book.