Highest temperature in Wellington on July 20?

Platform comparison

Market context

Wellington’s highest temperature on 20 July 2026 is the real-world event this contract tracks, with the market currently pricing a 12°C outcome at 100% probability, leaving zero chance for any lower range. On Polymarket, traders lock USDC on Polygon using conditional tokens to back this specific temperature bracket, and the 0% YES price for alternative outcomes reflects near-total consensus that the day will not exceed 12°C.

Historical mid-July maxima at Wellington International Airport (NZWN) typically cluster between 6°C and 13°C, with 12°C appearing frequently in recent MetService records for similar dates [2]. The current 100% frontrunner aligns with this pattern, as extreme cold snaps below 6°C or heat spikes above 13°C are rare in Wellington’s winter climate, making the 12°C band the statistically dominant outcome.

Traders should monitor MetService New Zealand’s daily forecasts for NZWN and Wunderground’s real-time hourly logs, which serve as the official resolution source [1][2]. Any sudden shift in wind direction from the prevailing south-south-westerly, currently at 24 mph, could alter the maximum temperature, so watching the BBC Weather update for NZWN and MetService’s 24-hour outlook is critical before settlement closes at 12:00 UTC on 20 July [3].

Sources: 1 · 2 · 3

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

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

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.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like PolyGram trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.