Highest temperature in Paris on July 13?

Platform comparison

Market context

Paris is currently enduring a red-alert heatwave, with Monday 13 July seeing temperatures edge down slightly to 34–36°C in the city while the intense heat persists across Île-de-France [2]. The market’s 1% implied probability on a specific high-temperature outcome reflects the crowd’s view that such an extreme spike is unlikely given the current cooling trend, even as France’s weather service confirms the heat episode will last at least until mid-week [2].

Historical July peaks in Paris often exceed 35°C during sustained heatwaves, yet the marginal drop today suggests the probability of a record-breaking spike remains low compared to the July 4 market which settled at 100% likelihood for its range [1]. This divergence highlights how platform mechanics alter risk perception: Polymarket displays raw implied probabilities with zero trading fees and no KYC for volumes under $1,500, whereas Kalshi uses decimal odds, charges up to 7% per trade, and mandates full US-only KYC [1]. Betfair similarly applies 2–5% commission and requires identity verification from the first trade, creating a structural friction absent on the on-chain venue [1].

Traders should monitor Météo-France’s daily bulletins for any sudden atmospheric shifts, as the service notes only a first easing is expected along the Atlantic slope early this week [2]. The settlement relies exclusively on Wunderground data from Paris-Le Bourget Airport, meaning local micro-climate variations in the city centre will not alter the outcome. While Polymarket settles automatically via USDC and the UMA oracle, off-chain books like Kalshi settle in USD via CFTC clearance, adding a regulatory layer that may delay resolution compared to the instant on-chain finality [1].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We read Highest temperature in Paris on July 13? from four platform perspectives: Polymarket (on-chain CLOB), Kalshi (CFTC-regulated exchange), Betfair Exchange (sports book exchange), Smarkets (peer-to-peer betting exchange). Polymarket's live mid is the canonical probability; the side-by-side columns benchmark fees, KYC, settlement currency and deposit rails so you can choose the venue that fits your jurisdiction and trade size.

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

Polymarket vs Kalshi — which is better?

Depends on your location. Kalshi is CFTC-regulated, US-only with full KYC. Polymarket is global, on-chain, no KYC up to $1,500. Polymarket has ~10x higher liquidity but higher regulatory risk.

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.

Which platform is accessible globally?

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

Are all these platforms regulated?

No. Kalshi is CFTC-regulated (US). Betfair and Smarkets are UK Gambling Commission licensed. Polymarket operates without explicit regulation — a different risk profile than a regulated sportsbook.