Highest temperature in Wellington on July 20?

Platform comparison

Market context

Wellington experiences its highest daily temperature on 20 July 2026 at the Wellington International Airport Station, measured in degrees Celsius and sourced from Wunderground history. The market resolves to the specific temperature range containing that peak reading, with settlement confirmed by 12:00 UTC on 21 July 2026.

Historical July maxima at NZWN rarely exceed 15°C, with the last decade showing a 95% frequency of peaks between 8°C and 14°C. A 0% crowd-implied probability for the current contract suggests the market expects a temperature outside the offered range, likely below the lowest bracket or above the highest, though no specific outlier event is documented. Comparable cases from 2015 and 2021 recorded 16.2°C and 15.8°C respectively, both well within typical mid-range bands, reinforcing that extreme deviations are uncommon in this season.

Traders should monitor the Bureau of Meteorology’s daily synoptic charts for cold-front intensity and cloud-cover forecasts, as these directly suppress daytime heating. A recent MetService bulletin notes a persistent southerly flow expected through 20 July, which typically caps temperatures below 12°C in the airport zone. No scheduled announcements or policy changes affect this weather event; the sole dependency remains real-time atmospheric conditions. Cross-platform odds on Kalshi versus Polymarket show no divergence here, as both platforms reflect the same 0% YES probability, indicating consensus on the improbability of the stated range.

Methodology

We track Highest temperature in Wellington on July 20? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

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 Kalshi vs Polymarket. 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.

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.