Mostly Right: Fundamental data for prediction markets

Access real-world data right on Kalshi and Polymarket.

Trade prediction markets with the actual real-world fundamental data in front of you. Mostly Right puts ground-truth data directly on Kalshi and Polymarket contract pages — the same fundamental data these markets settle on, right next to the odds. WHAT YOU GET TODAY • Live observations from the settlement station: temperature, dewpoint, humidity, wind — with the raw METAR text on hover. • A full-day timeline: observed temperatures so far, condition icons, and a NOW marker, aligned to the market's local settlement day. • Model forecasts side by side: GFS, HRRR, ECMWF, ICON, Météo-France, JMA and more, plus MOS guidance for US stations — each model's projected day high and an hour-by-hour temperature heatmap. • Switch models instantly and see which ones are running hot or cold against the observations. • Support for more markets coming soon. COVERAGE • Kalshi: daily high/low temperature markets for 19 US cities. • Polymarket: daily temperature markets for 40 international airports. • On a market we don't cover yet? Hit "Request data" and tell us what you trade — requests decide what goes live next. SOURCES Observations from NOAA/NWS aviation weather (METAR/ASOS) and the Iowa Environmental Mesonet archive. Forecasts via Open-Meteo and IEM MOS. Every number is sourced and timestamped, so you can judge the implied odds against reality without leaving the page. NO SETUP No account and no configuration — install, open a covered market, and the panel is there. °F/°C units, the forecast trend line, and a usage-data opt-out live in the panel's settings. You can also ask for email alerts on the markets you care about. FOR DEVELOPERS The same data powers the Mostly Right SDK on npm (@mostlyrightmd/weather). The extension is the live demo. Mostly Right is independent and not affiliated with Kalshi or Polymarket. Data is informational only and is not financial advice.