Highest temperature in Milan on July 21?

Platform comparison

Market context

The market tracks the peak Celsius temperature recorded at Milan’s Malpensa International Airport on 21 July 2026, with settlement confirmed via Wunderground’s daily history for the LIMC station. Today’s live reading at Malpensa shows 21°C, but the market resolves only the day’s maximum, not the current snapshot [2].

Historical July peaks at Malpensa typically range between 28°C and 34°C, making the current 0% YES probability for any outcome implausible unless the market is mis-specified or the resolution criteria exclude valid data. In comparable 2023–2025 summers, 31°C and 30°C emerged as the most frequent highs, aligning with Polymarket’s frontrunner outcomes of 38% for 31°C and 32% for 30°C [1]. A programmatically sound approach would query Wunderground’s API at 12:00 UTC on 22 July, parse the LIMC daily max, and map it to the nearest predefined range.

Traders should monitor the European Heatwave Watch from the Copernicus Emergency Management Service, which issues daily alerts for extreme temperature events across Italy, and check MeteoMilano’s 72-hour forecast updates for Malpensa-specific anomalies. A sudden shift in the 0% probability would likely stem from a data gap at Wunderground or a misalignment between the market’s range definitions and the actual recorded value, both of which are common in weather-based prediction markets.

Sources: 1 · 2

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 Fees. 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.

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.