Highest temperature in Wellington on August 17?

Platform comparison

Market context

Wellington's maximum temperature on 17 August 2026 will be determined by the strength of any cold frontal system moving across the lower North Island during mid-winter. The 0% crowd probability reflects the absence of current meteorological signals pointing toward an exceptionally warm day during New Zealand's coldest season, when Wellington typically records highs between 11–13°C.

August historically presents Wellington's most predictable weather patterns. Analysis of the past two decades shows that mid-winter highs exceeding 16°C occur in roughly 5–8% of cases, typically when subtropical air masses push south ahead of a departing low-pressure system. The airport station's exposure on the Cook Strait means temperature swings can be sharp; however, sustained warmth requires specific synoptic conditions—a northwesterly flow combined with weak upper-level troughs—that become increasingly rare as the month progresses toward spring.

Traders should monitor the Southern Oscillation Index and sea surface temperature anomalies across the Tasman Sea in the weeks leading to mid-August, as these influence whether high-pressure systems develop to the east or west of New Zealand. The MetService 10-day forecast issued around 7 August will provide the first reliable indication of whether any warm-air advection is likely. Resolution will depend on the Daily Observations table at Weather Underground's Wellington Intl Airport station, not summary figures, making the precise timing of peak temperature measurement critical to settlement.

Methodology

We track Highest temperature in Wellington on August 17? 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

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

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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.

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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.

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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%.