Highest temperature in Wellington on August 12?

Platform comparison

Market context

Wellington's maximum temperature on 12 August 2026 will be determined by the strength of any cold frontal system moving across the lower North Island during the Southern Hemisphere winter. Current crowd sentiment reflects deep uncertainty, with the 0% implied probability suggesting traders are awaiting clearer atmospheric signals before committing positions. The settlement window closes at midday on the day itself, meaning real-time observations from Wellington International Airport will be the decisive factor rather than forecasts issued weeks in advance.

August temperatures in Wellington typically range between 7–13°C for daily highs, though winter variability is substantial. Historical data shows that on 12 August alone, recorded maxima have fluctuated from as low as 8°C to peaks near 16°C depending on whether anticyclonic or frontal systems dominate. The current flat probability distribution suggests the market is genuinely uncertain about which temperature band will prevail, rather than indicating any systematic bias toward warmer or colder outcomes.

Traders should monitor the MetService forecast updates from late July through early August, as these will clarify whether a cold front or high-pressure system is positioned to influence Wellington on the target date. Sea-surface temperatures around New Zealand remain a secondary factor affecting winter air masses. The resolution will draw exclusively from Weather Underground's Daily Observations table at Wellington International Airport, not summary figures, so any discrepancy between reported sources will favour the granular observational data.

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.

UK Frequently Asked Questions

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.

Is Polymarket legal in the UK?

Polymarket is accessible to UK traders but is not UKGC-licensed. It operates under US CFTC jurisdiction. UK residents face no domestic legal prohibition on using it, but UKGC consumer protections do not apply. For UKGC-regulated alternatives, Betfair Exchange and Smarkets offer similar prediction-style markets.

Do I pay tax on prediction market profits in the UK?

UKGC-licensed platform profits (Betfair, Smarkets) are typically tax-free gambling winnings for UK individuals. Polymarket profits involve USDC crypto transactions, which HMRC treats as Capital Gains Tax events. Keep full transaction records and report via Self Assessment if gains exceed £3,000 per tax year.

How do I deposit on Polymarket from the UK?

UK traders typically fund Polymarket via Coinbase UK, Kraken or Revolut — buying USDC with GBP and transferring to a Polygon-compatible wallet (MetaMask, Coinbase Wallet). Polymarket's onboarding walks you through the bridging process. Typical GBP-to-USDC conversion costs 0.5–1%.