Highest temperature in Wellington on August 18?

Platform comparison

Market context

Polymarket has this contract anchored near certainty on the 12°C band, with the order book implying 0% for Yes on the current framing even though the market is still open until midday UTC. The practical read for a trader is simple: the contract settles on the highest reading in Weather Underground’s Daily Observations table for Wellington Intl Airport Station, so the intraday maximum, not the summary tile, is what matters.

For context, Wellington’s August climatology is firmly cool, with typical daytime highs around 11–12°C, and the recent forecast flow has kept the ceiling close to that range rather than pointing to a late-winter spike. Comparable winter days in Wellington usually resolve through modest bands rather than tail outcomes, which is why the market has been pricing a narrow outcome set rather than a broad temperature distribution.

The main catalysts are the forecast updates and any change in the station’s observed midday warmth before the 12:00 UTC cut-off. Traders watching the contract should focus on whether southerly winds ease enough to allow a brief lift into the 12–13°C bands, because that is where the conditional tokens on Polygon can still reprice if fresh observations push the daily high one band higher. Around settlement, the key dependency is not a headline forecast, but the specific Weather Underground table entry that locks in the day’s maximum.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Wellington on August 18? 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.

UK Frequently Asked Questions

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.

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%.