Highest temperature in Paris on July 20?

Platform comparison

Market context

The market tracks the peak Celsius reading at Paris-Le Bourget Airport on 20 July 2026, with the current crowd-implied probability for any outcome above the frontrunner sitting at 0%. Programmatic traders should note the resolution source is Wunderground’s daily history for LFPB, requiring automated scrapers to fetch the specific timestamped maximum rather than relying on aggregate forecasts. The 100% probability assigned to the 24°C range suggests the crowd views this as a near-certainty, likely anchored to recent seasonal norms where mid-July highs in Paris typically cluster between 22°C and 26°C[1].

Historical data from BBC Weather and The Weather Network shows current readings at Le Bourget hovering around 21–23°C, with northerly winds and excellent visibility tempering extreme heat spikes[2][3]. Comparable cases from previous July 20s in Paris show temperatures rarely exceeding 30°C unless a sustained Mediterranean heatwave occurs, making the 24°C bracket a statistically robust anchor. A trader building a conditional order bot would weight this range heavily, treating deviations as low-probability outliers unless a specific atmospheric catalyst emerges.

Key catalysts include the European Centre for Medium-Range Weather Forecasts’ (ECMWF) mid-month ensemble updates, which often refine heatwave probability 10–14 days ahead. Traders should monitor the Met Office’s daily UK and Europe outlook for any sudden shifts in southerly flow, as these directly correlate with Parisian temperature spikes. Recent news from the BBC highlights that northerly winds currently dominate, reducing immediate heat risk and supporting the market’s confidence in the 24°C outcome[2]. Automated systems should flag any ECMWF model divergence indicating a 5°C+ upward shift as a potential arbitrage signal.

Sources: 1 · 2 · 3 · 4

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 Polymarket Review UK. 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.

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.