Highest temperature in Paris on July 3?

Platform comparison

Market context

Paris is bracing for a scorching heatwave on 3 July 2026, with temperatures forecast to surge well above seasonal averages across northern France. A powerful heatwave is pushing temperatures sharply higher, bringing blazing sunshine, hot afternoons and very warm nights, while dry conditions dominate with almost no rain expected.

Historical context frames the current 0% YES probability as a misreading of the event’s severity. France recently recorded its hottest day ever, with a national thermal indicator of 29.8°C and regional highs reaching 44.3°C in Landes, while Paris itself hit 44°C during an early heatwave. In the Paris region, temperatures are now expected to reach 36–38°C, possibly up to 40°C, making the 0% probability inconsistent with the trend of extreme heat.

Traders should monitor Meteo France’s red heatwave alerts, which cover 54 departments and indicate persistent high temperatures around the clock. The key catalyst is the official Wunderground reading for Paris-Le Bourget Airport, which will settle the market at 12:00 UTC on 3 July. Programmatic approaches would involve scraping real-time Wunderground data, cross-referencing with Meteo France’s hourly forecasts, and executing conditional orders based on temperature thresholds exceeding 35°C. Recent reports from Al Jazeera confirm over 101 million people in Europe face temperatures above 35°C, including 50 million in France, reinforcing the likelihood of extreme heat in Paris.

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Methodology

We track Highest temperature in Paris on July 3? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

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

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 Polymarket Review UK 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.