Highest temperature in Paris on August 11?

Platform comparison

Market context

Paris is already in the grip of a broader French heatwave, and the last 24–48 hours have brought fresh warnings that conditions are likely to stay hot rather than break sharply. Weather services for Paris show a sunny, very warm day profile, with AccuWeather flagging an extreme high-temperature warning and a forecast near 32–34°C, while other short-range outlooks cluster around a similar mid-30s peak. [12][8]

The current 0% implied chance for a lower band looks detached from both the seasonal baseline and recent Paris extremes. August averages in Paris are far below heatwave levels, but the city has a long tail of hot days, including a 39.5°C August record for 11 August at Paris-Montsouris and a broader Paris all-time high of 41.9°C. That matters because once a strong hot spell is established, the market often resolves around whether the afternoon peak lands in the low, mid or upper 30s rather than whether heat is present at all. [4][6][15]

Traders should watch the evolving official and model-led forecasts through the day, because the settlement is tied to the highest reading recorded on Weather Underground’s Daily Observations for Paris-Le Bourget Airport, not a generic daily high summary. Any update that shifts cloud cover, wind, or the timing of peak insolation can move the final outcome by a degree or two, and late revisions remain possible until the first datapoint for 12 August is published. [1][12]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in Paris on August 11? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Prediction Today, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

UK Frequently Asked Questions

Where can I trade this market with the lowest fees?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Prediction Today. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

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Do I pay tax on prediction market profits in the UK?

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