Highest temperature in Madrid on June 29?

Platform comparison

Market context

The underlying real-world event is the highest temperature recorded at Adolfo Suárez Madrid-Barajas Airport on 29 June 2026, measured in degrees Celsius. Polymarket prices this contract today with a 0% probability for the YES outcome, implying the crowd believes the temperature will fall outside the specific range being traded. This near-zero pricing is stark when viewed against historical June data for Madrid, where the average high reaches 31.8°C and the month’s warmest day typically occurs on 30 June [6]. Recent records show extreme volatility; the highest maximum temperature in June 2026 was 38.3°C on 22 June, while a historic peak of 40.7°C was recorded on 28 June 2019 [7][9]. Furthermore, a severe heatwave in late June 2026 saw temperatures exceed 110°F (43°C) in parts of Spain, causing hundreds of excess deaths [3][5]. These comparable cases suggest that a 0% probability may be an overreaction to current short-term conditions rather than a reflection of the month’s true thermal potential.

Traders should monitor the official weather bulletins from AEMET and real-time updates from Wunderground, which serves as the resolution source for this market [1]. The settlement window ends at 12:00 UTC on 29 June 2026, meaning any temperature spike in the early morning hours could alter the outcome before the market closes. A critical catalyst is the ongoing heatwave that has already broken numerous records across Spain, with Madrid experiencing its warmest night on record recently, where temperatures did not drop below 26.2°C [5]. On-chain mechanics on Polygon, using USDC and conditional tokens, allow for rapid position adjustments as new data arrives, but the 0% pricing suggests a lack of confidence in a range breach despite the extreme heat context [1]. The dependency on Wunderground’s specific station data means traders must verify that the airport station aligns with the broader regional heat trends reported by AccuWeather and PredictWind [2][4]. Ignoring the recent news of record-breaking heat in Spain could lead to a significant mispricing if the temperature on 29 June aligns with the historic peaks seen just days prior [3].

Sources: 1 · 2 · 3 · 4 · 5

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 Kalshi UK, 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 Kalshi UK. 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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Kalshi UK 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.