Highest temperature in Paris on August 11?

Platform comparison

Market context

On 11 August 2026, the highest temperature recorded at Paris-Le Bourget Airport will determine the settlement of this market. The resolution hinges on the Daily Observations table from Weather Underground rather than the Day High & Low summary section, a distinction that matters when intraday readings diverge from rounded daily figures. This specificity reflects how different weather data providers report temperature extremes, and traders should verify which source each platform uses for settlement before committing capital.

Historical August temperatures in Paris cluster between 24–28°C on average, though heat waves have pushed readings above 30°C in recent years. The 2022 European heat event saw Paris reach 35°C in mid-August, whilst the cooler August 2015 peaked near 26°C. Current crowd probability sitting at 0% YES suggests either the market is pricing an unusually narrow temperature band or reflects low liquidity typical of niche weather derivatives. Across platforms, Polymarket and Kalshi diverge significantly on weather markets: Polymarket uses decimal odds with tighter spreads on volatile events, whilst Kalshi's binary structure and regulatory reach in the US often draws different trader demographics. Betfair and Smarkets offer fractional odds but typically lower volume on European weather specifics.

Traders should monitor European weather forecasting updates from Météo-France and the European Centre for Medium-Range Weather Forecasts (ECMWF) as August approaches. Atmospheric patterns in late July will signal whether high-pressure systems or Atlantic disturbances dominate early August. Platform liquidity may improve as the settlement date nears, though weather markets historically remain thin compared to political or financial events.

Methodology

We read Highest temperature in Paris on August 11? from four platform perspectives: Polymarket (on-chain CLOB), Kalshi (CFTC-regulated exchange), Betfair Exchange (sports book exchange), Smarkets (peer-to-peer betting exchange). Polymarket's live mid is the canonical probability; the side-by-side columns benchmark fees, KYC, settlement currency and deposit rails so you can choose the venue that fits your jurisdiction and trade size.

Resolution & payout

Polymarket settles via UMA Optimistic Oracle on Polygon. A proposer posts the outcome with a bond, the two-hour window runs, then the smart contract pays USDC.

Kalshi settles USD through the CFTC-regulated clearinghouse — the cleanest variant, with heavier KYC. Betfair Exchange settles in account currency (GBP/EUR), net of 2-5% commission. Smarkets follows the same model as Betfair with a lower default 2% commission.

FAQ

What does Polymarket cost vs Kalshi?

Polymarket: 0% fees, only Polygon network costs (~$0.01/trade). Kalshi: up to 7% per trade plus spread. For high-frequency traders, Polymarket is dramatically cheaper.

Is Betfair a Polymarket alternative?

Only partially. Betfair Exchange is UK-focused with a sports-betting emphasis; they have politics markets but with thinner liquidity than Polymarket. Settlement in GBP/EUR, 2-5% commission on winnings.

What about Smarkets as an alternative?

Smarkets is a UK betting exchange with a lower default commission (2%) than Betfair. Liquidity on political markets is below Polymarket, comparable to Kalshi. Geo-blocked in many jurisdictions.

Are all these platforms regulated?

No. Kalshi is CFTC-regulated (US). Betfair and Smarkets are UK Gambling Commission licensed. Polymarket operates without explicit regulation — a different risk profile than a regulated sportsbook.

Which platform supports Klarna/SOFORT?

Directly: none. Polymarket accepts only USDC on Polygon. Robinhood Prediction Markets offers a fiat on-ramp via Klarna or SOFORT (DE/AT/CH) and converts internally to USDC for the Polymarket order book. T+1 processing.