Highest temperature in Paris on August 3?

Platform comparison

Market context

Paris is starting the day with the temperature ceiling already shaped by a recent run of exceptional summer heat across France, even though the market settles on the highest reading at Paris-Le Bourget Airport rather than city-centre conditions. The key near-term change in the last 24–48 hours is that the broader French weather story has stayed tilted towards heat stress, with *Le Monde* reporting on 25 July that France was heading into its fourth heatwave of the year, which keeps attention on whether Paris can revisit the upper end of its August range rather than sit near the seasonal average.[20]

For context, Paris’s August climatology is much lower than the levels implied by the market’s current 1% YES price. Long-run weather summaries put typical August daytime highs in the low- to mid-20s Celsius, while the most extreme August readings historically reach around 40°C in the city.[10][17] Recent coverage of the 2026 European heat episodes also noted Paris pushing into the low 40s during the June heat wave, which is a reminder that very hot outcomes are possible when continental high-pressure systems dominate.[9][11] Against that backdrop, a 1% chance suggests traders are treating the required top-end outcome as a genuine outlier, not a base case.

The main catalyst to watch is the late-summer synoptic pattern over northern France: if a heat dome, dry south-easterly flow, or prolonged sunshine locks in over the Paris basin, the chance of an extreme daytime maximum rises quickly; if Atlantic fronts or cloudier, breezier conditions move through, the ceiling drops sharply. Because settlement uses the Paris-Le Bourget Airport Station reading from Wunderground, the market is sensitive to local airport-specific effects as well as the regional forecast, so traders will watch the final 24-hour forecast cycle, any updated French weather alerts, and whether conditions peak before the 12:00 UTC settlement cut-off.[1][20]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Prediction Today 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.