Highest temperature in Wellington on June 30?

Platform comparison

Market context

On 30 June 2026, Wellington International Airport will record its peak daily temperature, a single real-world datum that determines the outcome of this prediction market. The crowd currently assigns a 0% probability to the “YES” outcome, implying near-total consensus that the temperature will fall outside the specified range. This stark pricing suggests traders view the event as effectively impossible under current conditions, yet handicappers must question whether this reflects genuine meteorological certainty or merely a contrarian blind spot where value might lurk.

Historical patterns frame this probability with caution. June in Wellington typically sees highs between 14°C and 16°C, rarely exceeding 19°C, though extreme outliers have occurred—such as the 30.3°C record at Kelburn during a recent heatwave [3]. Even so, the airport station’s coastal exposure usually moderates extremes, making a temperature spike beyond the range statistically unlikely. Yet the 0% pricing ignores the non-zero chance of an anomalous southerly surge or unseasonal warmth, a scenario that previously broke June records [6].

Traders should monitor MetService’s daily forecasts for the coming week, particularly any announcements of southerly wind shifts or heatwave developments [6]. Dependencies include the timing of the settlement window (ending 12:00 UTC on 30 June) and Wunderground’s real-time data feed, which may lag during extreme events. While consensus remains firmly against the range, the absence of any positive probability leaves room for value if forecast models later indicate a contrarian temperature spike.

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

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

FAQ

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.

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.