Highest temperature in Wellington on July 8?

Platform comparison

Market context

The underlying real-world event is the highest temperature recorded at Wellington International Airport on 8 July 2026, measured in degrees Celsius. Current crowd-implied probability for a "YES" outcome sits at 0%, yet the market frontrunner is 12°C at 47%, with 13°C trailing at 40%. This divergence reflects how Polymarket prices conditional tokens on the Polygon network using USDC, where traders buy shares in specific temperature ranges rather than betting on a binary event. The on-chain mechanics ensure real-time odds updates as liquidity flows, capturing the collective view that winter conditions will likely keep temperatures near the seasonal average.

Historical climatology for Wellington in July shows an average daytime maximum near 11–12°C, with typical ranges of 10–14°C under winter conditions[2]. While recent heatwaves have pushed Wellington (Kelburn) to record highs of 30.3°C, such extremes are outliers against the dominant trend of winter cooling[4][8]. The strongest long-term trend indicates a +1.7°C increase in winter temperatures over 90 years, yet this gradual warming does not currently justify pricing for significantly higher ranges in the immediate settlement window[5]. Traders reading the current probability should frame expectations around the historical distribution centred on 14°C, where data leans toward this outcome as the statistical norm[3].

Key catalysts for traders include daily weather bulletins from NIWA and real-time updates from Wunderground, which serves as the official resolution source[4]. Any sudden announcements regarding atmospheric river events or unseasonal warm air intrusions could shift odds rapidly, though no such forecasts are currently active. Traders must monitor the settlement dependency on the specific Wellington Intl Airport Station data, as regional variations between Kelburn and the airport can alter the final range. With the settlement window ending 2026-07-08T12:00:00Z, the market remains tightly priced around the 12–13°C range until new meteorological data emerges.

Sources: 1 · 2 · 3 · 4 · 5

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

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 Polymarket Scam? trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

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.