Highest temperature in Paris on July 12?

Platform comparison

Market context

Paris is bracing for its third heatwave of 2026, with meteorologists warning that temperatures in the Paris region could climb between 36°C and 40°C this weekend and into next week [8]. The city is already experiencing its hottest summer since 1947, following record-breaking highs in June where Paris’ Charles de Gaulle Airport hit 104°F (45.6°C) on 24 June [3]. This historical context explains the current 0% crowd-implied probability for any temperature range exceeding the likely forecast; traders on Polymarket see no chance of a record-shattering spike, whereas Kalshi’s decimal odds format would reflect this as a near-zero price, while Betfair and Smarkets might show negligible liquidity due to the event’s perceived impossibility.

Traders should monitor Météo-France’s daily heat alerts and Wunderground’s real-time updates for the Paris-Le Bourget Airport Station, the official resolution source for this market [2]. The third heatwave is expected to peak over the coming days, with peaks possibly reaching 40°C in the South, West, and Paris region [8]. Unlike Kalshi, which relies on CFT-regulated data partnerships with The Weather Company, Polymarket uses Wunderground directly, creating a divergence in resolution reliability if data gaps occur. Fee structures also vary: Polymarket charges no fees on winning trades for some users, while Kalshi imposes a 2.5% fee on profits, and Betfair/Smarkets operate on commission-based models that could alter net returns on low-probability bets.

The convergence of three heatwaves in one summer, combined with June’s record highs, suggests July 12 will likely fall within the 36–40°C range, not exceeding it. This aligns with the 0% probability assigned by the crowd, as historical data shows Paris rarely surpasses 42°C even during extreme events [4]. Platform differences in KYC requirements further influence trader access: Kalshi mandates strict US identity verification, while Polymarket offers broader global access with lighter checks, and Betfair/Smarkets require EU-compliant KYC. These structural divergences shape how each book interprets and prices the same weather event.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares Highest temperature in Paris on July 12? specifically across Polymarket, Kalshi, Betfair Exchange and Smarkets. The live probability is the Polymarket mid; the comparison columns summarise each venue's fee structure, KYC, settlement currency and payment rails. Every CTA routes to Kalshi 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). On-chain settlement clears in minutes — the fastest payout path of the four.

FAQ

Which platform has the deepest liquidity?

Polymarket — by a wide margin. Top markets reach $50-500M volume, Kalshi ~$200M cumulative, Betfair similar. Deeper liquidity means your trade moves the quote less.

Is Betfair a Polymarket alternative?

Only partially. Betfair Exchange is UK-focused with a sports-betting emphasis; they have politics markets but with thinner liquidity than Polymarket. Settlement in GBP/EUR, 2-5% commission on winnings.

What about Smarkets as an alternative?

Smarkets is a UK betting exchange with a lower default commission (2%) than Betfair. Liquidity on political markets is below Polymarket, comparable to Kalshi. Geo-blocked in many jurisdictions.

Which platform is accessible globally?

Polymarket is geo-blocked in the US/UK/EU. Kalshi is US-only. Betfair and Smarkets are UK-restricted. Kalshi Alternative has a different geo footprint and routes to Polymarket's order book at 0% fees.

Which platform supports Klarna/SOFORT?

Directly: none. Polymarket accepts only USDC on Polygon. Kalshi Alternative offers a fiat on-ramp via Klarna or SOFORT (DE/AT/CH) and converts internally to USDC for the Polymarket order book. T+1 processing.