Highest temperature in London on July 12?

Platform comparison

Market context

London City Airport is recording today’s high of 29°C under sunny intervals, with the settlement window for the July 12, 2026 temperature market closing at noon UTC. The crowd-implied 0% probability on any outcome above the current range reflects the station’s historical July average high of 22°C (72°F) and the absence of extreme heat warnings for this date [2][4]. While London saw 40.2°C in July 2022 at Heathrow and St James’s Park, City Airport’s urban location and shorter exposure to record spikes make such extremes less likely here [7].

Traders should monitor the Met Office’s 7-day forecast updates and Wunderground’s daily history feed, the official resolution source, for any sudden shifts in temperature trends or heatwave announcements [3]. Recent NW3 Weather data shows July 10, 2026 hit 31.2°C, suggesting mild volatility but no sustained extreme heat pattern yet [8]. On Polymarket, this market uses implied probability (0% YES), whereas Kalshi and Betfair typically display decimal odds, and Smarkets offers fee-free trading for verified users—key divergences for cross-platform comparison [1].

Fee structures and KYC requirements also differ: Polymarket requires minimal verification for crypto users, while Kalshi mandates full US KYC, and Betfair/Smarkets cater to UK/EU audiences with varying identity checks. These platform mechanics shape liquidity and pricing efficiency on weather markets like this one, where real-time data from EGLC determines resolution.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares Highest temperature in London 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 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

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.

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