Trade: Highest temperature in Paris on May 15?

Market context

This market settles on the highest temperature recorded at Paris-Le Bourget Airport on 15 May 2026. The resolution uses historical weather data from Weather Underground, capturing the daily maximum in degrees Celsius. Settlement occurs at 12:00 UTC on that date, once the meteorological record is finalised.

Paris's mid-May temperatures typically range between 15–22°C, with occasional warm spells pushing into the mid-20s. Historical data from Le Bourget shows May 15th has seen highs of 18–20°C in most years, though the station recorded 25°C on this date in 2009 and 27°C in 2017. The current 0% implied probability on Polymarket's order book suggests traders are pricing in either extreme confidence in cooler outcomes or minimal liquidity across temperature brackets. The clustering of bids at lower ranges indicates the crowd expects temperatures below typical May averages, though the specific reasoning—whether seasonal forecasting models, longer-range climate patterns, or thin order books—remains opaque from current market depth.

European weather systems in May remain volatile, with Atlantic low-pressure systems competing against continental warming patterns. Traders monitoring this market should track late-April and early-May weather forecasts from Météo-France and European medium-range models, which typically gain reliability 10–14 days ahead. Any significant heatwave warnings issued in early May would likely shift the probability distribution sharply upwards. The settlement window's precision—requiring the exact daily maximum from a single airport station—means localised weather variation matters; cloud cover or wind patterns specific to the Île-de-France region could materially affect outcomes.

Resolution source

This market settles from the official outcome published at https://www.wunderground.com/history/daily/fr/bonneuil-en-france/LFPB. 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 Paris on May 15?" 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?

$9K in lifetime turnover and $52K 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 $9K 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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