Highest temperature in London on July 24?

Platform comparison

Market context

The event is the highest temperature recorded at London City Airport on 24 July, and the current crowd view of **0% YES** suggests traders are not assigning any meaningful chance to the upper temperature bands in the market’s range. On Polymarket, that probability is shown directly as a percentage; on Kalshi, the same view is usually expressed as contract prices that can be read as implied probabilities, while Betfair and Smarkets quote decimal-style odds that need converting into an implied chance and also need adjustments for commission. Polymarket’s market page currently shows the leading outcomes clustered around **28°C** and **29°C**, which is a useful reminder that summer London temperature markets often centre on the high-20s rather than extreme heat.[1]

For context, London’s July climate normally sits in the low-20s, with average late-July temperatures around **22.7°C** and frequent rain, so a finish in the high-20s usually requires a warmer-than-average spell rather than a routine summer day.[4] That makes the shape of the market more dependent on whether the day develops a brief afternoon peak than on the morning reading. Past London heat episodes show how quickly probabilities can reprice when forecasts shift: earlier July 2026 heatwave coverage cited London highs of **34°C** and multi-day heat alerts, but those conditions are not the default for the city in July.[3][2]

The key catalysts are the day’s forecast updates, cloud cover, and the timing of any convective showers or sea-breeze effects that can cap the maximum at London City Airport before the settlement window closes at 12:00 UTC. Traders following the same event across platforms should also note the practical differences: Polymarket is cash-settled through share prices, Kalshi through contract prices, and Betfair/Smarkets through matched betting odds with commission, so the same weather view can look very different once fees and spreads are included. Because this market resolves to the single highest reading on Wunderground for EGLC, an early spike matters more than the day’s average temperature.[1][4]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares Highest temperature in London on July 24? 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 UK, 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.

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 UK 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.