Highest temperature in Paris on July 9?

Platform comparison

Market context

An intense early-July heatwave, driven by a strong high-pressure ridge and clear skies, has already pushed Paris temperatures to highs near 35–36 °C on 7–8 July, with the heatwave expected to persist for a few more days before a slight drop. On Polymarket, this contract currently prices the 33 °C outcome at 41% and 34 °C at 40%, while the specific 34 °C YES share trades at $0.39 (implied 38.5%), reflecting a collective view that the peak is likely to land in the 33–34 °C band rather than the extreme 41 °C suggested by some media reports.

Historically, Paris has seen record highs of 42.6 °C in July, but the current red alert from Météo-France for 54 departments, coupled with daytime temperatures soaring to 40 °C in numerous areas, frames this event as an outlier where the 1% implied probability for the highest range may be underpriced given the sustained ridge. The night before stays warm, with temperatures potentially staying above 28 °C even at midnight, creating dangerous afternoon heat that officials warn residents to avoid between 12:00 p.m. and 6:00 p.m.

Traders should monitor the scheduled red alert status and any emerging storm forecasts later in the week, which could bring relief and alter the peak temperature, as noted in recent coverage by Sortiraparis confirming the heat is back with a peak near 36 °C on Tuesday. The on-chain mechanics on Polygon, using USDC and conditional tokens, ensure real-time odds updates as traders buy and sell shares, so the market view shifts instantly with new weather data from Wunderground for the Paris-Le Bourget Airport Station.

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

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

FAQ

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 PolyGram. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

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.