Highest temperature in Paris on May 31?

Platform comparison

Active sub-markets

Market context

On 31 May 2026, the highest temperature recorded at Paris-Le Bourget Airport will fall into one of several defined ranges. This market settles on actual meteorological data from Wunderground's historical records for that specific station, making it a straightforward physical measurement with no ambiguity in the underlying event itself.

Historical May temperatures at Le Bourget show considerable year-to-year variation. The station's May average high sits around 20°C, but extremes have ranged from below 10°C during cool springs to 29°C or higher during warm years. The 0% implied probability currently reflected across major platforms suggests traders view an exceptionally high outcome as unlikely, though the exact threshold varies by book. Polymarket's decimal odds format and Kalshi's binary structure handle temperature bands differently—Polymarket typically offers broader ranges with tighter odds, whilst Kalshi's regulatory framework in the US may exclude certain temperature thresholds entirely. Betfair and Smarkets, operating under UK and EU licensing respectively, often display these markets with fractional odds that can obscure the true probability spread compared to Polymarket's decimal presentation.

The relevant catalyst is the European seasonal weather pattern forecast for late May 2026. Météo-France and the UK Met Office typically issue 10-day forecasts around 21 May, providing the most actionable signal for traders. Longer-range climate models from ECMWF become available earlier but carry wider uncertainty bands. Fee structures differ materially: Polymarket charges no maker fees and 2% taker fees, whilst Kalshi's commission sits at 3–5% depending on volume, and Betfair's exchange model charges 5% on net winnings, affecting the true cost of position entry across platforms.

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 Polymarket Alternative, 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). Polymarket Alternative routes every trade directly into Polymarket's on-chain settlement, which is why payouts land fastest.

FAQ

Is this market available outside the US?

Polymarket Alternative is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

What does it cost to trade on Polymarket Alternative?

Zero. Polymarket Alternative routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

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?

Not under $1,500 of lifetime trading volume. Above that threshold, Polymarket Alternative triggers a quick verification flow that finishes in 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.