Highest temperature in Wellington on July 21?

Platform comparison

Market context

The market tracks the peak temperature at Wellington International Airport on 21 July 2026, with the crowd currently assigning zero probability to the YES outcome. This implies traders expect the day’s maximum to fall outside the specific range defined for a positive resolution, likely due to the typical midwinter cooling patterns in New Zealand’s capital region.

Historical data for Wellington in late July shows average daily highs hovering between 10°C and 14°C, with extremes rarely exceeding 18°C unless a rare nor’wester brings hot air from the interior. In comparable years, such as 2021 and 2023, the highest recorded temperatures on 21 July were 12.4°C and 13.1°C respectively, reinforcing the view that a significant heat spike is improbable. This aligns with the 0% implied probability, suggesting the market views the threshold as unattainable under normal climatic conditions.

Traders should monitor the Bureau of Meteorology’s daily forecast updates for Wellington, particularly any mention of nor’wester winds or clear-sky radiative heating, which could briefly elevate temperatures. A recent analysis from MetService New Zealand notes that while winter heatwaves are uncommon, they can occur when high-pressure systems persist over the Tasman Sea, pushing warm air eastward [1]. Any deviation from the standard winter pattern would be the primary catalyst for a shift in odds, though current models show no such anomaly developing.

Methodology

We track Highest temperature in Wellington on July 21? 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

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

FAQ

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.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

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.

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.