Highest temperature in Paris on August 19?

Platform comparison

Market context

The Paris-Le Bourget Airport weather station will record temperatures throughout 19 August 2026, with this market settling on whichever range captures the single highest reading logged in Weather Underground's Daily Observations table that day. The 0% crowd probability suggests traders either expect cooler conditions or are avoiding the market entirely due to uncertainty over data sourcing—a common friction point when resolution depends on a specific platform's granular data rather than official national meteorological records.

Historical August temperatures at Le Bourget show a median high of around 25–26°C, with extremes ranging from 18°C in cooler years to 35°C during heat waves. The 2022 European heat event saw Paris record 40°C, though such peaks remain statistical outliers. Comparing across platforms, Kalshi and Betfair typically offer tighter temperature bands with decimal odds, whilst Polymarket's range-based structure can obscure the precise probability density; traders migrating from traditional bookmakers often misjudge tail-risk pricing when ranges widen. The reliance on Weather Underground's Daily Observations table rather than Météo-France's official data introduces basis risk that most European weather traders avoid, explaining the depressed probability.

No scheduled weather alerts or climate announcements typically drive August 19 forecasts; the market's value depends on real-time meteorological conditions two years forward. Traders should monitor European summer circulation patterns and any Atlantic blocking systems that develop in late July 2026, as these determine whether continental heat reaches the Île-de-France region. The settlement window closes at midday UTC, creating a narrow window for final observations and potential data reconciliation disputes.

Methodology

This page compares Highest temperature in Paris on August 19? 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.

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.

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.

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.