Trade: Highest temperature in Madrid on May 12?

Market context

This market settles on the highest temperature recorded at Madrid-Barajas Airport on 12 May 2026. The resolution will draw from historical weather data via Wunderground, capturing the single daily maximum in Celsius. The current order book implies a 20% probability for the YES outcome, reflecting traders' collective assessment of whether temperatures will reach a particular threshold on that specific date.

Madrid's May temperatures typically range between 18–28°C, with occasional peaks above 30°C during early heat waves. Historical data from the airport station shows that exceeding 32°C in mid-May occurs roughly once every three to four years, whilst temperatures above 35°C remain uncommon before late May. The 20% implied probability suggests traders are pricing in a moderately warm but not exceptional day, consistent with late-spring conditions rather than early-summer heat.

Traders should monitor European weather pattern forecasts as May approaches, particularly the position of high-pressure systems moving northward from North Africa. The North Atlantic Oscillation and Mediterranean sea-surface temperatures will influence whether warm continental air masses reach the Iberian Peninsula. Any significant climate anomalies or seasonal forecasts released by AEMET (Spain's national meteorological agency) in the weeks preceding the settlement date could shift market pricing, as would real-time weather model updates in early May showing persistent heat advection into central Spain.

Resolution source

This market settles from the official outcome published at https://www.wunderground.com/history/daily/es/madrid/LEMD. A proposer submits the final result to the UMA optimistic oracle on Polygon; the two-hour dispute window closes and payouts clear in USDC.

How to trade this market step by step

The mechanics for trading "Highest temperature in Madrid on May 12?" are the same as any other PolyGram event contract. Each YES share resolves to $1 if the event happens, or $0 if it doesn't. The current price between 0¢ and 100¢ is the market's probability estimate, set live by the order book.

1. Sign in on polygram.ink with your email — no full KYC under $1,500 lifetime trading volume.
2. Deposit USDC on Polygon (lowest fees, ~$0.01 per transaction) or Ethereum. Funds credit after 12 confirmations.
3. Pick a side. Buy YES if you believe the event will happen; buy NO if you think it won't. The current YES price reflects the market's collective probability.
4. Size your position. If you stake 100 USDC at 50% YES, you'll receive shares that pay $200 if YES resolves true — a 100% gross return. If NO resolves, your shares are worth $0.
5. Set risk controls (optional). Stop-loss, take-profit, and limit-order types all supported. Use the trade ticket's slippage box to cap your maximum entry price.
6. Wait for resolution. When the event resolves on-chain via the UMA optimistic oracle, the winning side settles to 100¢ automatically and USDC hits your balance within seconds. Withdrawable to any wallet you control.

How active is this market?

$16K in lifetime turnover and $40K of resting liquidity puts this market in the below the median by volume for weather contracts on PolyGram. Order-book depth is strong — order books support five-figure trades with single-cent slippage.

Last 24 hours alone saw $14K in turnover, well above the lifetime daily-average for this market — a clear sign of news catalysing trader activity right now.

The market has been open for under a month — fresh enough that information asymmetry remains a real factor.

Higher-volume markets tend to have tighter spreads and faster price discovery — meaning the displayed YES/NO percentages are more likely to reflect the true crowd-implied probability rather than a single trader's directional view.

Key terms

YES / NO share

A binary outcome token that pays $1.00 if the underlying claim resolves true (YES) or false (NO), and $0 otherwise. The market price between 0¢ and 100¢ is the implied probability.

CLOB

Central limit order book. The matching engine that pairs YES buyers with NO buyers (effectively the same trade). Polymarket's CLOB on Polygon executes trades on-chain via the conditional-tokens framework.

Liquidity

USDC capital sitting in resting limit orders inside the order book. Deeper liquidity means smaller slippage on large trades and a tighter bid-ask spread.

UMA optimistic oracle

The on-chain dispute system that settles each Polymarket market. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution.

Slippage

The difference between the displayed mid-price and your fill price. Affects market orders most; limit orders avoid slippage but may take time to fill.

Conditional token

ERC-1155 outcome share issued by Gnosis Conditional Tokens on Polygon. The token type that resolves to $1.00 or $0.00 at settlement.

See the full prediction-market glossary →

Frequently asked questions

Risk and regulatory note

Prediction-market positions can lose 100% of staked capital. Outcomes are uncertain by definition — historical accuracy of crowd-implied probabilities is high in aggregate but not for any single market. PolyGram does not provide investment advice. Trade only with capital you can afford to lose.

Regulatory status varies by jurisdiction. Germany, the United States, and most EU countries treat Polymarket-style event contracts under one of three frameworks: financial derivative, gambling product, or unregulated novel asset. Consult local counsel before trading.

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