Highest temperature in Madrid on August 2?

Platform comparison

Market context

Polymarket prices this Madrid airport temperature contract at 0% YES, so the chain is effectively assigning no live probability to any single outcome in the current view, even though settlement is paid in USDC on Polygon through conditional tokens if the correct temperature band is matched. Because the market resolves to the highest temperature recorded at Adolfo Suárez Madrid-Barajas Airport on 2 August, the practical reference point is the day’s maximum, not the average or the morning reading.

For context, Madrid’s August climate is usually hot enough that the upper 30s Celsius are plausible, but the daily spread still matters for a one-number settlement. AccuWeather’s August 2026 outlook for Madrid shows daily highs mostly in the low-to-mid 30s °C, while historical extremes at Madrid, Retiro include August maxima of 40.7°C, underlining that a heat spike is possible even if it is not the base case.[1][12] Polymarket’s own outcome ladder for this market has recently concentrated around 36°C and 37°C, which is a useful benchmark for how traders have been reading the forecast distribution rather than the exact airport reading.[13]

A trader should watch the Spanish and local forecast updates closest to the settlement window, especially any heat alerts, cloud cover changes, or wind shifts that could alter the airport’s peak temperature by a degree or two. Reuters reported Spain’s first official heatwave of 2026 in June, a reminder that strong subtropical ridging can build rapidly over the Iberian Peninsula and push temperatures higher than seasonal norms.[16] The key dependency is the Wunderground airport history page, because Polymarket resolves from that station’s recorded daily maximum and revises only until the next day’s first datapoint is published.[13]

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

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

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.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

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.