Highest temperature in Wellington on August 9?

Platform comparison

Market context

The real-world event here is simple: whether the highest temperature recorded at Wellington International Airport on 9 August reaches the temperature band that would make **YES** pay out, using Weather Underground’s **Daily Observations** table rather than the broader day-high summary. In a prediction market, a **YES** share pays if the contract condition is met, while a **NO** share pays if it is not, so the key question is not whether the day feels cold overall but which recorded Celsius reading is the day’s maximum under the market’s specific resolution rule.

The current **0% YES** implies traders see the target temperature band as very unlikely, and that fits Wellington’s winter profile. August in Wellington is usually cool: long-run climate pages put typical daily highs around **12°C**, with many days clustered between roughly **9°C and 12°C**, and the forecast for 9 August points to a cool, breezy day with rain or drizzle early on and a forecast high around **12°C** to **15°C** depending on the source[1][2][5][9][10]. For a market like this, compare the implied probability with how often weather stations actually print a higher-than-expected midday spike, rather than with the headline forecast alone.

The main catalysts to watch are the latest Wellington airport forecast updates, any shift in wind direction or cloud break-up, and the final observation sequence posted through the day, because the settlement source is the station log rather than a summary page[2][11][12]. Wellington’s weather can change quickly with passing showers and strong winds, so even a modest warm-up between morning drizzle and afternoon clearing can matter if the contract’s temperature band sits near the forecast range[2][10][14].

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

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

UK Frequently Asked Questions

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 Prediction Market UK. 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.

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%.