Highest temperature in Wellington on July 21?

Platform comparison

Market context

Wellington is experiencing a chilly, cloudy midwinter day with temperatures hovering around 15°C at the International Airport, while winds gust south-westerly at 24 mph. The prediction market for the highest temperature on 21 July 2026 currently shows a crowd-implied probability of 0% for any outcome above the consensus favourite, which is firmly locked at 12°C. This 100% assignment to 12°C suggests the market views any deviation as statistically negligible, effectively treating the underdog scenarios as non-starters.

Historical midwinter data for Wellington typically sees daily maxima ranging between 10°C and 14°C, with 12°C representing a robust median for this period. Comparable cases from the last decade show that temperatures dropping below 7°C are rare anomalies, often linked to extreme polar air masses, whereas spikes above 15°C are equally uncommon without significant northerly flow. The current 0% probability for lower ranges aligns with this stability, indicating the consensus has correctly priced in the typical thermal floor for late July.

Traders should monitor the Bureau of Meteorology’s daily synoptic charts for any sudden shifts in the Southern Ocean pressure systems, which could introduce contrarian value if a rare cold snap develops. While no specific announcements are pending, the dependency on real-time Wunderground data means that any discrepancy between forecast models and observed station readings could create fleeting liquidity opportunities. Recent weather bulletins confirm the persistent south-westerly flow, reinforcing the 12°C favourite, though a shift to northerlies would be the primary catalyst for a contrarian angle on higher temperatures.

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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

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 Who Will Win. 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 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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Who Will Win 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.