Will more than 410 tornadoes occur in the United States in May 2026?

• 01
  Active signal

  Resolution-risk observation firing

  Spread is wide enough that intraday moves overstate any tradeable edge.

• 02
  Spread cost

  Wide spread — 16.0¢

  Bid-ask spread is wide enough that intraday moves overstate any tradeable advantage. Most of the headline pp move would be eaten by spread on a market order.

Each factor is grounded in a single named metric you can verify on this page — probability, volume, liquidity, signal, resolution state. No predictions, no prose hallucinations.

This market will resolve according to the number of tornadoes recorded in the United States during the specified month, based on the monthly count published on the National Centers for Environmental Information U.S. Tornadoes Time Series page (see: https://www.ncei.noaa.gov/access/monitoring/tornadoes/time-series). Only tornadoes appearing in the final NCEI dataset for that month will count. As of market creation, the relevant report is scheduled to be released on June 8, 2026, at 5:01 PM GMT+1 or 11:01 AM ET (Release schedule: https://www.ncei.noaa.gov/access/monitoring/dyk/monthly-releases). The market will resolve based on the first relevant tornado count published on the NCEI tornado time-series page after this scheduled release time. If the value published after this scheduled release time is labeled preliminary, it will still determine resolution, and the market will resolve independently of any subsequent revisions, corrections, or retroactive adjustments. The market will not resolve based on any preliminary values published before the scheduled release time. If no data is published by the scheduled release time, or if the NCEI website is temporarily unavailable, this market will remain open until that data is made available. If the relevant data is not made available by the date of the next scheduled publication ET, this market will resolve based on available data for the most recent prior month. If the NCEI website becomes permanently unavailable, this market will resolve using another credible source.

Categories come from a deterministic engine: manual overrides (highest priority) → sports hard markers → event-tag rules → keyword rules → Gamma category hint → default. The engine is versioned in category-overrides.ts; methodology lives at /methodology.