55% — When will the next Category 5 hurricane form
Leader: Before Dec 1, 2026 at 55% · Kalshi 55% · 4 contracts · $100 volume · medium confidence
Updated 2026-08-24 15:13:06 UTC

Tracks the leading outcome in a winner-take-all prediction market set with 4 outcomes.

Why this matters:
This probability measures the chance that a Category 5 hurricane will form before September 1, 2026—just three weeks away. Markets currently estimate this at 4%, reflecting the rarity of Category 5 storms and the advanced stage of the 2026 Atlantic hurricane season. The assessment depends on current sea surface temperatures, atmospheric conditions, and historical frequency: Category 5 hurricanes form in only a small fraction of Atlantic seasons. If tropical activity accelerates significantly in late August, or if satellite data shows unusual ocean warming patterns, this probability would likely rise. The main near-term catalyst is early September itself—if no Category 5 forms by September 1, the market will shift focus to the October 1 and November 1 contract windows, when hurricane season typically peaks. Real-time monitoring of developing tropical systems and sea surface temperature anomalies will be the primary drivers of probability movement.

Key factors:
- Only 3 weeks remain until the September 1 deadline, and no major tropical systems are currently forecast to rapidly intensify to Category 5 strength
- Historical data shows Category 5 hurricanes are rare events; fewer than 20 have formed in the Atlantic basin since 1850, with clustering in certain decades
- Current Atlantic sea surface temperatures and atmospheric indicators would need to shift substantially to support rapid intensification
- September 1 serves as the immediate resolution date; if it passes without a Category 5, market focus shifts to later-season windows when conditions typically favor stronger storms
- Operational hurricane forecasting models and real-time satellite imagery of tropical systems will provide the clearest signals for probability revision

Contracts:
- When will the next Category 5 hurricane form?: Before Dec 1, 2026 — 55¢ Kalshi $0 (weight 0%)
- When will the next Category 5 hurricane form?: Before Nov 1, 2026 — 19¢ Kalshi $0 (weight 0%)
- When will the next Category 5 hurricane form?: Before Oct 1, 2026 — 14¢ Kalshi $100 (weight 100%)
- When will the next Category 5 hurricane form?: Before Sep 1, 2026 — 3¢ Kalshi $0 (weight 0%)

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## Methodology

SimpleFunctions aggregates live YES-side prices from Kalshi and Polymarket contracts bound to this question. For binary topics the headline is the liquidity-weighted mid-price (weight = log(1 + 24h volume) × freshness, where freshness is 1.0 if updated <24h, 0.7 if <7d, 0.4 otherwise). For multi-outcome (winner-take-all) topics the headline is the current leader's price — disjoint outcomes are never arithmetically averaged. Snapshots refresh every 5 minutes during market hours.

## SF Signal

- SF Index, regime, and 30d Brier calibration are computed separately and surfaced at https://simplefunctions.dev/admin/calibration.
- No SimpleFunctions index / regime / calibration signal is bound to this topic yet — the headline above is market-derived only.

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*Last verified: 2026-08-24T13:20:51.962Z*

By SimpleFunctions — https://simplefunctions.dev/

Cite as: "55% per prediction markets (SimpleFunctions, August 2026)"
Canonical: https://simplefunctions.dev/answer/nextcat5hurdate
Full data: https://simplefunctions.dev/api/public/query?q=When%20will%20the%20next%20Category%205%20hurricane%20form
Provider: SimpleFunctions — https://simplefunctions.dev