Highest temperature in Wellington on August 19?

Platform comparison

Market context

Wellington International Airport's daily maximum temperature on 19 August 2026 will be recorded and binned into a range bracket. The market resolves against Weather Underground's Daily Observations table—the granular, station-level dataset rather than the summary Day High & Low figures. This distinction matters for programmatic resolution: traders building automated feeds should query the correct WU endpoint and validate against historical discrepancies between the two sources, which occasionally occur during data synchronisation delays or sensor recalibration periods.

August is Wellington's late winter month, with historical daily maxima typically ranging from 10–14°C. The 0% crowd probability suggests the market may be testing an extreme upper bound or reflects sparse liquidity rather than genuine confidence in a cold outcome. Comparable August days at Wellington Airport show that temperatures above 18°C occur roughly once per decade; sub-5°C maxima are rarer still. A trader evaluating this market should cross-reference the MetService archive and NIWA's climate summaries to establish the actual distribution of August extremes, then assess whether the range brackets offered reflect realistic tail risk or mispricing.

Southern Hemisphere winter patterns in 2026 will depend on the Antarctic Oscillation phase and any lingering La Niña or El Niño conditions forecast by NOAA and the Bureau of Meteorology. Traders should monitor MetService's 14-day outlook updates (published Tuesdays and Fridays) and any unusual pressure systems tracking toward New Zealand in early-to-mid August. Conditional order logic could trigger hedges if ensemble models show a warming anomaly, though such events remain statistically improbable for Wellington's winter season.

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

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.

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%.