Highest temperature in Paris on May 31?

Platform comparison

Active sub-markets

Market context

On 31 May 2026, Paris-Le Bourget Airport will record a daily high temperature. The settlement hinges on which Celsius range contains that single highest reading, with resolution sourced from Weather Underground's historical data for that station. The 0% crowd probability suggests either extreme confidence in a specific range or minimal liquidity across the book at present.

May 31st falls in late spring for the Paris region, when daily highs typically range between 18–24°C, though outliers occur. Historical data from the same station shows May can produce temperatures above 28°C during heat waves, whilst cooler years see highs near 15°C. The 2022 European heat wave pushed May temperatures across northern France well above seasonal norms; conversely, the exceptionally wet May 2013 kept highs depressed. Traders should cross-reference long-range forecasts from Météo-France and European weather models, though their skill at 18-month lead times remains limited. The specific settlement source—Weather Underground's Paris-Le Bourget records—differs from Météo-France's official station data, potentially creating basis risk if discrepancies emerge.

Kalshi's binary-style resolution and Polymarket's implied-probability display will frame this differently for users comparing platforms. Betfair and Smarkets typically offer decimal odds formats that obscure the underlying probability distribution across temperature bands. Fee structures vary: Kalshi charges flat settlement fees, whilst Polymarket applies percentage-based liquidity fees. Geographic KYC restrictions mean UK traders face different access profiles across these venues. The current 0% reading reflects either a dominant consensus on one outcome or sparse order flow; watching for range-specific activity as 2026 approaches will signal where genuine disagreement lies.

Methodology

This page compares Highest temperature in Paris on May 31? specifically across Polymarket, Kalshi, Betfair Exchange and Smarkets. Live odds come from the Polymarket order book; the other venues' contract details are maintained manually because their APIs aren't directly comparable. Every CTA routes to Kalshi Alternative UK, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Settlement is the biggest difference between the four platforms: Polymarket on-chain in USDC (instant), Kalshi USD via CFTC (T+1), Betfair and Smarkets in local currency via bank withdrawal (T+1 to T+3). Kalshi Alternative UK routes every trade directly into Polymarket's on-chain settlement, which is why payouts land fastest.

FAQ

Where can I trade this market with the lowest fees?

On Kalshi Alternative UK, which mirrors the Polymarket order book at 0% fees. 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.