Highest temperature in Milan on July 31?

Platform comparison

Market context

The underlying event is whether the highest temperature at Malpensa Airport in Milan ends up inside the contract’s settlement band on 31 July 2026, with Wunderground’s daily history page as the source of truth. July in Milan is normally warm enough that daytime highs cluster around the high 20s to low 30s Celsius, with long-run July averages around 28–29°C and typical mean maxima near 28.6°C, so the market is really about whether today’s peak reaches the upper end of that seasonal range rather than about a cold-day outcome.[4][9][15]

That framing makes the current 0% yes price look more like a disagreement with the market design than a view on Milan climate. Historical July data show that highs of 30–31°C are routine, while extreme summer spikes can go far higher: Milan’s all-time July record highs are around 38°C, and one recent report described a 91.4°F average daily temperature during a severe heatwave, underscoring how quickly the city can move into much hotter territory when continental air masses dominate.[3][4][17] By comparison, prediction-market pricing appears to imply that traders see no credible path into the relevant temperature bucket, whereas standard weather history would suggest the contract should not be treated as a near-zero event in a normal Milan summer.

The main catalysts are the day’s actual temperature curve at Malpensa, cloud cover, rain timing, and any late-model changes to the regional heat pattern; by the settlement deadline, a brief early-afternoon surge can matter as much as the daily mean. Traders usually watch the airport observation stream and short-range forecasts for shifts in afternoon maxima, especially if a hot, dry plume arrives or convective cloud keeps temperatures suppressed. No separate official schedule event is needed here, but any updated Wunderground reading at the airport before 12:00 UTC is decisive for how the contract settles.[5]

Sources: 1 · 2 · 3 · 4 · 5

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

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

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 vs Polymarket. 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.

Do I need to KYC for this market?

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