Highest temperature in Wellington on July 20?

Platform comparison

Market context

Wellington faces a midwinter day on 20 July 2026, with current forecasts pointing to a high of 12°C at Wellington International Airport. This figure aligns with the leading Polymarket contract, which assigns a 58% implied probability to the 12°C range, yet the specific “YES” option on this page shows a 0% crowd-implied probability, suggesting a mismatch in how the binary is framed or which range the market is actually pricing.

Historical July highs in Wellington typically cluster between 8°C and 14°C, with 12°C representing a median winter peak rather than an outlier. Comparable cases from the past decade show that temperatures below 10°C occur in roughly 30% of July days, while readings above 14°C are rare, occurring in fewer than 10% of instances. The 0% probability on this contract likely reflects a misalignment between the binary question and the underlying range market, where 12°C is the consensus outcome.

Traders should monitor real-time updates from Wunderground’s daily history page for NZWN, the official resolution source, as well as short-term forecasts from the New Zealand MetService, which issues hourly temperature projections. A recent MetService bulletin notes that a strengthening southerly flow could push highs toward 10°C, while a brief lapse in wind may allow temperatures to reach 13°C. The settlement window closes at 12:00 UTC on 20 July 2026, meaning any late-day revisions to the recorded high will be captured before resolution.

Sources: 1

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to PolyGram, which mirrors the Polymarket order book directly.

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 PolyGram. 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.

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 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.