Highest temperature in Paris on August 5?

Platform comparison

Market context

Paris-Le Bourget Airport will be judged on the single highest temperature reached during the day, so the practical question is whether the afternoon peak stays in the upper 20s or pushes into the low 30s Celsius. Current public forecasts for Paris on 5 August sit around 29°C for the day’s high, with some services showing a band from roughly 24°C to 29°C and dry, sunny conditions rather than an extreme-heat setup.[12][9] That makes a 0% crowd-implied yes price look like a very sceptical take on the prospect of a one-day spike above the relevant range bucket, especially if the market’s “YES” outcome is tied to a particular threshold rather than the full scale.

The historical frame matters because Paris can produce sharp summer swings, but late-summer averages are still modest compared with the recent June heatwave that took Paris to 40.9°C and drove broader French records into the mid-40s elsewhere.[13][17] For comparison, long-run August guides for Paris cluster around daytime highs near 23°C to 26°C, which is well below the levels that would force the upper market bands to win.[5][6] On platforms such as Polymarket, the quote is shown as an implied probability; on Kalshi, Betfair and Smarkets, traders usually have to translate between decimal odds and probability, while fees, spreads and KYC availability differ by venue, which can change the apparent attractiveness of the same temperature view.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares Highest temperature in Paris on August 5? specifically across Polymarket, Kalshi, Betfair Exchange and Smarkets. The live probability is the Polymarket mid; the comparison columns summarise each venue's fee structure, KYC, settlement currency and payment rails. Every CTA routes to Polymarket Alternative, which mirrors the Polymarket order book at 0% fees.

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

Polymarket vs Kalshi — which is better?

Depends on your location. Kalshi is CFTC-regulated, US-only with full KYC. Polymarket is global, on-chain, no KYC up to $1,500. Polymarket has ~10x higher liquidity but higher regulatory risk.

Which platform has the deepest liquidity?

Polymarket — by a wide margin. Top markets reach $50-500M volume, Kalshi ~$200M cumulative, Betfair similar. Deeper liquidity means your trade moves the quote less.

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.

Which platform is accessible globally?

Polymarket is geo-blocked in the US/UK/EU. Kalshi is US-only. Betfair and Smarkets are UK-restricted. Polymarket Alternative has a different geo footprint and routes to Polymarket's order book at 0% fees.

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.