Highest temperature in Paris on August 1?

Platform comparison

Market context

The underlying event is the **highest temperature observed at Paris-Le Bourget Airport on 1 August 2026**, as logged by Wunderground for that station. The market settles on the day’s peak reading, so the practical question for a trader is whether the station prints a top value in the high 20s or drifts into 30°C-plus territory before the day rolls over in the source feed.

The current crowd price of **0% YES** is best read as a stale or mechanically depressed quote rather than a strong signal that the reading will be extreme. The live Polymarket page itself shows a much more normal summer distribution, with **28°C** the leading outcome at **60%** and **29°C** at **24%**, while the market also notes that revisions remain possible until the first datapoint for the following date is published. That means programmatic traders should not anchor on the headline probability alone; they should model the likely daily maximum from hourly observations, then watch for late-afternoon updates and any source adjustments that can still alter the final settlement value.[3]

For catalysts, the most relevant inputs are the day’s synoptic setup, the official forecast track from Météo-France and ECMWF, and whether any heat episode strengthens or weakens over northern France. Recent reporting has shown that France has already endured exceptionally intense heat this summer, with Paris reaching **40.9°C** during the June heatwave and national temperature records being broken elsewhere in the country, which keeps upside tail risk in play even in a city-centre summer market.[7][14][15][16] A bot or conditional-order workflow should therefore watch the forecast consensus for Paris, local cloud cover and wind changes, and any updated weather warnings that could shift the afternoon maximum by one or two degrees.

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.

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.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

Do I need to KYC for this market?

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