Highest temperature in Wellington on July 21?

Platform comparison

Market context

Wellington's highest temperature on 21 July 2026 will be measured at the airport weather station and resolved against Wunderground's historical records. The market currently shows 0% probability across all temperature brackets, reflecting the distant settlement date and inherent uncertainty in seasonal forecasting. On Polygon, traders are pricing this contract in USDC, with conditional tokens issued for each temperature range; the zero probability suggests minimal trading activity or consensus that current price discovery mechanisms haven't yet engaged with this July event.

July is Wellington's coldest month, with mean maximum temperatures around 11–12°C and extremes rarely exceeding 16°C. Historical data from the past two decades shows that temperatures above 15°C on a July day occur infrequently, whilst readings below 8°C are common. The airport station's exposure on the Rongotai Peninsula means wind chill effects often suppress apparent warmth, even on days with moderate solar input. These seasonal baselines matter because they anchor what "warm" means in Wellington's winter context.

The Southern Hemisphere's winter weather patterns in 2026 will depend on sea surface temperatures across the Tasman Sea and the strength of any high-pressure systems tracking across New Zealand in late July. The National Institute of Water and Atmospheric Research (NIWA) publishes monthly outlooks roughly three weeks in advance, which will become the primary catalyst for probability shifts as the settlement window approaches. Traders monitoring NIWA's June 2026 forecast and any El Niño or La Niña updates will have early signals about whether July conditions favour above-average or below-average temperatures for the region.

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.

FAQ

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 Kalshi UK. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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 fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Kalshi UK trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.