Highest temperature in Paris on August 3?

Platform comparison

Market context

Paris on 3 August will be judged by the day’s **highest reading at Paris-Le Bourget Airport**, not by an end-of-day close, so the key question is whether the midday heat peaks enough to land in the upper Celsius bands. The market’s **1% YES** implies traders are assigning only a small chance to an extreme outcome, which is consistent with a Paris August climatology that usually sits well below heatwave levels and with weather services pointing to typical daytime maxima around the low-to-mid 20s Celsius for the month.[13][16][18]

Historical context suggests that very high outcomes in Paris are possible but rare, and they usually depend on a continental heat dome rather than normal summer conditions. Recent French heat episodes have pushed Paris close to or above 40°C, including a reported 40.9°C in the city during the June 2026 heatwave, while the country’s broader record heat has been much higher in the south.[6][10][17][20] For this contract, that means the price is less about seasonal averages and more about whether an anomalous late-summer surge reaches the airport station specifically, where local siting and timing can matter as much as the wider Paris headline.

Traders should watch the next 24 hours of model updates, any fresh French heat alerts, and whether the current warm spell is expected to peak before the market’s 12:00Z settlement cut-off. Because resolution uses Wunderground’s daily history page for the station, a late-morning spike can matter more than the eventual afternoon cool-down if it is not captured before settlement; that makes the intraday temperature curve and the local forecast run-up more relevant than the daily average.[20] On the crypto side, this is a straightforward USDC-settled event, so broader BTC and ETH moves matter mainly through risk appetite and liquidity rather than the weather outcome itself.

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 does a transaction cost on Polygon?

Polygon gas is typically under $0.01 per transaction. A full trade cycle (Approve + Order + Fill) totals around $0.03 — compared to $5-50 on Ethereum mainnet.

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.

Which crypto markets exist on Polymarket?

Currently active markets include BTC/ETH/SOL price targets, halving dates, ETF approvals, hard-fork outcomes and Layer-2 TVL thresholds. The list updates weekly; biggest volume sits on BTC and ETH price forecasts.

Are crypto prediction markets taxable in the US?

In the US, prediction market gains are typically treated as ordinary income or short-term capital gains depending on holding period. Consult a tax professional for your specific situation — we cannot provide tax advice.