Highest temperature in Paris on July 23?

Platform comparison

Market context

Paris is set for a single-day temperature read on the Paris–Le Bourget Airport station, with the settlement based on the highest recorded Celsius value for 23 July from the day’s Wunderground history page. That makes this a straightforward weather-number market: the final outcome is not the noon reading, but the day’s peak, so any automated workflow should key off the maximum daily temperature rather than intraday snapshots.

The current 0% YES pricing looks very far below Paris July climatology. Historical July data put average highs around 27°C, and Paris is typically warm in midsummer, with ordinary summer afternoons often landing in the 20s rather than the low 20s or below. On that basis, a 25°C outcome is already consistent with a fairly normal July day, while a materially cooler result would usually require an unusually subdued air mass or cloud/rain suppression.

For traders using bots, conditional orders, or a polling script, the practical trigger is the station’s final daily maximum, not city-wide weather headlines. The useful inputs are the hourly forecast trend, any forecast revisions from the evening before, and whether local convective showers or an Atlantic cool-down are likely to cap the day’s high below the 25°C band. Since the market settles from a specific station feed, programmatic monitoring should watch that location directly and map forecast ranges to the relevant outcome buckets rather than relying on broader Paris forecasts.

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

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.

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.