Highest temperature in Wellington on August 21?

Platform comparison

Market context

Wellington International Airport will record its highest daily temperature on 21 August 2026, with the market asking which range in degrees Celsius that reading will fall into. The settlement hinges on data from Weather Underground's Daily Observations table at the airport station, creating a specific methodological anchor that differs from casual weather summaries.

August represents Wellington's late winter period, when daytime highs typically range between 11–14°C, though occasional warm northerly flows can push temperatures into the high teens. Historical August records at Wellington Airport show a maximum of 20.3°C (set in 1962), with readings above 18°C occurring roughly once per decade. The 0% crowd probability suggests traders are pricing in an expectation that the temperature will fall below the lowest available range option, or that no range has been offered at sufficiently attractive odds to justify backing any outcome. This compressed probability distribution is typical for weather markets with narrow historical variance and limited upside catalysts.

The key variables affecting the outcome are large-scale pressure systems crossing the Tasman Sea in late August. The New Zealand MetService issues extended forecasts roughly ten days before the date, with meaningful updates arriving five to seven days prior. Any significant anticyclonic system tracking towards the South Island could drive warm air northward into the Wellington region. Traders should monitor MetService outlooks and Southern Hemisphere circulation patterns from mid-August onward, as these will provide the clearest signal of whether anomalous warmth is plausible for that specific date.

Methodology

We track Highest temperature in Wellington on August 21? 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

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

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 Best Prediction Markets. 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.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

Do I need to KYC for this market?

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