Highest temperature in Paris on July 20?

Platform comparison

Market context

Paris-Le Bourget Airport is set to record its peak temperature for 20 July 2026, with the crowd currently pricing a 24°C outcome at 100% probability, effectively ruling out any chance of the temperature falling to 21°C or below. This near-certainty contrasts sharply with how traditional books like Betfair or Smarkets might express the same view; while they typically display decimal odds (such as 1.01 for 24°C), Polymarket uses implied probability directly, here showing 0% for the lower range. Kalshi, which also uses probability but mandates strict KYC and US residency, would likely mirror this pricing if the event were listed, though its fee structure and regulatory reach differ significantly from Polymarket’s global, lower-barrier model.

Historically, mid-July temperatures in Paris often hover between 22°C and 26°C, with 24°C representing a plausible median rather than an outlier. The current 0% probability assigned to “21°C or below” aligns with recent summer patterns where cooler days below 21°C are rare in this period, as seen in BBC Weather’s current reading of 21°C for the station, which reflects today’s conditions rather than the forecast for 20 July. Traders should monitor Meteo France’s weekly bulletins and any sudden shifts in northerly wind patterns, which could suppress temperatures; a recent BBC Weather update notes northerly winds at 3 mph, a factor that historically correlates with modest cooling if sustained through the settlement window.

Sources: 1 · 2

Methodology

This page compares Highest temperature in Paris on July 20? 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 Robinhood Prediction Markets, 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

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.

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.

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.

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. Robinhood Prediction Markets has a different geo footprint and routes to Polymarket's order book at 0% fees.