Highest temperature in Paris on August 18?

Platform comparison

Market context

The market is pricing zero probability that the highest temperature at Paris-Le Bourget Airport on 18 August 2026 will fall into whichever range this market represents—a striking consensus that warrants scrutiny. August in the Paris region typically sees daily highs between 24–27°C, with extremes occasionally reaching 30°C or beyond during heat waves. The 0% implied probability suggests traders are either confident the actual high will fall outside this specific temperature band, or the market has attracted minimal liquidity and reflects no genuine conviction.

Historical August temperatures at Le Bourget show considerable variability. The station recorded 40.3°C on 25 August 2003 during Europe's catastrophic heat wave, whilst August 2015 saw highs routinely exceed 30°C. Conversely, cooler Augusts have produced daily maxima in the low-to-mid 20s. Without knowing the exact temperature range this market covers, the 0% probability either reflects an implausibly narrow band or signals thin trading. If the range spans even 5°C, historical data suggests meaningful probability should attach to it.

Traders should monitor European summer weather patterns through July 2026, particularly Atlantic pressure systems and any developing heat dome scenarios. The Météo-France forecast issued in early August will provide the most reliable guidance for that specific week. Settlement hinges on Weather Underground's Daily Observations table at Le Bourget, which occasionally diverges from summary figures—a technical detail that could matter if temperatures cluster near range boundaries. The current 0% pricing leaves substantial value for contrarian positions if the range captures any plausible August outcome.

Methodology

This page reviews Highest temperature in Paris on August 18? 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 Who Will Win 2026, 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.

FAQ

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

What's the difference between YES and NO shares?

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Who Will Win 2026 trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.