Highest temperature in Paris on August 11?

Platform comparison

Market context

Paris’s highest temperature on 11 August will be set by the warmest reading in Weather Underground’s **Daily Observations** table for Paris-Le Bourget Airport, not the summary high-and-low figure. That matters because the market is resolved to a specific Celsius band, so a one-degree difference can change the outcome; Polymarket’s own market page currently shows the main cluster around 32°C and 33°C, while the implied probability on “YES” remains at 0% in your feed despite those listed prices being the practical reference for what traders are targeting.[1]

Historically, mid-August in Paris can still produce a wide spread of outcomes: the city’s 11 August record maximum is 39.5°C, and long-run August maxima commonly sit in the mid-20s Celsius, with occasional spikes far above that during heatwaves.[4][18] That context helps explain why a zero-priced state looks more like a stale or disconnected quotation than a true meteorological forecast. On platforms, the same event is framed differently: Polymarket and Kalshi quote contingent share prices that map to implied probabilities, whereas Betfair and Smarkets use decimal odds, so the same view can look visually different once fees and commission are included; accessibility also differs, with KYC and jurisdictional reach shaping who can actually participate.

The main catalysts are the local forecast trajectory, any heat alerts, and whether temperatures peak before or after the midday settlement cut-off, since the relevant window ends at 12:00 UTC. Current forecast services are still flagging very hot conditions for Paris, with AccuWeather showing an extreme-heat warning and The Weather Network projecting a 32°C high for the day, so traders will watch for any downtick in the official forecast path or cloud/rain timing that could cap the maximum.[10][6] Because the settlement source is station observations rather than a headline forecast, intraday updates at Paris-Le Bourget Airport are what matter most, especially if the day’s maximum is reached early or revised after the fact before the next day’s first datapoint is published.[1]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares Highest temperature in Paris on August 11? 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 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). On-chain settlement clears in minutes — the fastest payout path of the four.

FAQ

What does Polymarket cost vs Kalshi?

Polymarket: 0% fees, only Polygon network costs (~$0.01/trade). Kalshi: up to 7% per trade plus spread. For high-frequency traders, Polymarket is dramatically cheaper.

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. Polymarket Alternative 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.

Which platform supports Klarna/SOFORT?

Directly: none. Polymarket accepts only USDC on Polygon. Polymarket 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.