Highest temperature in Wellington on July 25?

Platform comparison

Market context

Wellington International Airport will record its highest temperature on 25 July 2026, with settlement determined by historical weather data from Wunderground. The market is currently pricing all temperature ranges at 0% implied probability, suggesting either a technical issue with the odds display or extremely thin liquidity across all brackets. This is unusual for a straightforward weather resolution event with a clear data source and defined settlement window.

July falls within Wellington's winter season in the Southern Hemisphere, when daytime highs typically range between 10–13°C. Historical records show that extreme heat during mid-winter is exceptionally rare; the airport station has recorded only a handful of days above 15°C in July across its multi-decade dataset. Comparable winter days at Wellington Airport suggest traders should anchor expectations around the 11–14°C range, with outcomes above 16°C representing genuine outliers tied to unusual atmospheric conditions or warm northerly flows.

The primary catalyst affecting this outcome is the Southern Oscillation Index and broader Pacific weather patterns in mid-2026. Any significant warm-air advection event—typically driven by a strong subtropical ridge or cut-off low system—would be the mechanism for elevated temperatures. Traders should monitor MetService New Zealand forecasts in the week preceding 25 July for any signals of anomalous warmth. The 0% crowd probability across all brackets suggests this market may lack active participation; cross-platform comparison with Kalshi or other venues would clarify whether this reflects genuine consensus or simply sparse order flow.

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

FAQ

Where can I trade this market with the lowest fees?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is PolyGram. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

What's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.