Highest temperature in Paris on August 4?

Platform comparison

Market context

Polymarket currently prices the highest Paris reading on 4 August mostly in the **31°C–32°C** band, with 31°C leading at **35%** and 32°C close behind at **34%**, so the contract is trading as a fairly tight distribution rather than a one-way bet.[1] On Polymarket, these prices are USDC-denominated shares on Polygon and settle via conditional tokens, so the market is effectively asking where the day’s top temperature at Paris-Le Bourget Airport will land against Wunderground’s final daily high for that station.[1]

That pricing sits well below the extreme readings seen in Paris during the June 2026 heat wave, when Paris reportedly reached **40.9°C** and parts of France went above **44°C**, but it is much closer to the city’s typical August profile, where long-run guides cluster daytime highs around the low-to-mid 20s Celsius and sometimes higher in warm spells.[9][10][11] For a trader, the key point is that the market is not forecasting the month’s average weather; it is pricing one station’s single daily maximum, which can move a band higher even if the broader Paris forecast looks ordinary.[1][10]

The main catalysts are the near-term forecast updates for **Paris and Île-de-France**, especially any shift in cloud cover, wind, or afternoon convection that can cap the peak temperature, and late-breaking heat advisories from French forecasters or major weather services.[14][19] Because settlement uses Wunderground’s Paris-Le Bourget history page, traders should watch the intraday forecast into the afternoon rather than only the overnight outlook, since the contract resolves on the highest reading recorded during the day, not the forecast maximum.[1]

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.

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.

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 Kalshi UK trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.