Highest temperature in Paris on August 1?

Platform comparison

Market context

The event is the maximum temperature recorded at Paris-Le Bourget Airport on 1 August, settled by the day’s Wunderground history page. Paris in August is usually warm rather than extreme, with average highs around 25–26°C, but the city’s August record high is much higher, so a 0% YES price suggests the market is treating an outright range hit as very unlikely rather than impossible.[3][9][11]

Historically, 1 August has delivered a broad spread of outcomes, which is why day-specific temperature markets can move sharply when forecasts shift. One Paris record table shows 1 August highs ranging from the mid-teens to the mid-30s Celsius, with a 35.5°C maximum recorded in 2013, while broader August history places the month’s all-time Paris high near 40°C.[3][6][15] For a market settled on the airport station rather than central Paris, the relevant reading can differ modestly from city-centre averages, but the main frame is still whether the day ends up in a normal warm band or a heatwave tail event.[3][9]

Traders should watch short-range temperature guidance for Île-de-France, especially any late-summer ridge or Atlantic breakdown that changes afternoon maxima into the settlement window. August in Paris can bring warm, dry spells, but cloud cover, rain and onshore airflow can cap highs quickly, and even late-summer setups can swing several degrees within 48 hours.[10][16][17] On the crypto side, the contract settles in USDC, so broader BTC and ETH moves matter mainly through risk appetite and liquidity rather than the weather outcome itself; if spot weakens or funding turns one-sided, smaller weather markets can still see thinner order books and sharper repricing around forecast updates.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically this overview focuses on on-chain pricing: Polymarket's live mid comes from the Polygon conditional-token order book and settles automatically in USDC. The other three venues — Kalshi, Betfair, Manifold — sit alongside as off-chain reference points so you can see how the contract translates across regulatory and settlement regimes.

Resolution & payout

Settlement is on-chain via UMA Optimistic Oracle. A proposer posts the outcome with a bond, a two-hour dispute window opens, then the smart contract lifts winning conditional tokens to 1 USDC and sends payments to holders' wallets automatically. No withdrawal fees beyond Polygon gas.

Off-chain venues (Kalshi, Betfair, Smarkets) settle in local fiat through bank-side clearing — faster than SWIFT, slower than on-chain. Manifold pays no real cash.

FAQ

What are crypto prediction markets?

Crypto prediction markets are on-chain smart contracts where you buy YES or NO shares on a future crypto event (e.g. "BTC above $100k by year-end"). The market price between 0¢ and 100¢ is the implied probability.

Why USDC and not ETH or USDT?

USDC is the Polygon standard — audited reserves (Circle, monthly attestation), deepest order book, low gas costs. ETH volatility would distort probability quotes; USDT has thinner Polygon liquidity than USDC.

Can I use Bitcoin directly?

No, Polymarket operates exclusively in USDC on Polygon. You can bridge BTC to USDC via an exchange or bridge service and deposit on Polygon — typically 10-30 minutes processing time.

How does UMA secure the resolution?

The UMA Optimistic Oracle uses a bond system: a proposer posts a bond, a two-hour challenge window opens. On dispute the losing side forfeits the bond — financial incentive for honest resolution.

How volatile are crypto prediction markets?

Crypto markets react to spot prices — a 5% BTC move typically shifts a "BTC above X by date" market 10-20%. Polymarket crypto market liquidity is usually six-figure USD, sufficient for active trading.