Highest temperature in Madrid on May 22?

Platform comparison

Active sub-markets

Market context

The market will resolve off the highest temperature recorded at Adolfo Suárez Madrid-Barajas Airport on 22 May, with the final value coming from Wunderground’s daily history page once the day is closed. For a programmatic trader, the key input is not the citywide forecast headline but the station-level maximum and the exact settlement cut-off; intraday spikes around mid-afternoon matter more than the morning run rate. Madrid often posts a fairly broad diurnal range in May, with average daily highs around the low-to-mid 20s °C, but the airport sits on the city’s outskirts and can run a little differently from central observations.

That backdrop helps explain why the crowd’s current pricing is extremely one-sided. Official and commercial forecast pages have recently centred on the low 30s °C for today, with Polymarket’s own event page showing 32°C as the dominant outcome and comparable weather climatology suggesting that low-30s readings are plausible in late May, though still above the monthly norm. The all-time Madrid record is far higher, at 40.7°C, so this market is really about whether today’s warmth extends just enough to nudge the airport observation into the next bracket rather than anything approaching an extreme.

The main catalysts are the afternoon forecast updates from Spain’s AEMET and any short-term revision from the Met Office or similar aggregators as the heat peaks. A bot watching this market would typically monitor hourly temperature, cloud cover and wind shifts, then map the latest station forecast into the adjacent settlement bands before the day’s maximum is finalised. With the close at 12:00 UTC, the practical question is whether the warmest reading arrives early enough to be captured in the source record and whether any late-day cooling arrives before the airport’s official maximum is locked in.

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). The odds column is filled only where we have clean data — that avoids the made-up numbers that get a network demoted when search engines cross-check against the source venue.

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?

On PolyGram, which mirrors the Polymarket order book at 0% fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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 does it cost to trade on PolyGram?

Zero. PolyGram routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

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.

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.