Highest temperature in London on July 13?

Platform comparison

Market context

London City Airport is forecast to reach a maximum of 24°C on 13 July 2026, with Met Office data suggesting a range of 26–28°C for the wider city, yet the crowd-implied probability for a YES outcome on this specific market sits at just 6%[1][3]. This low probability contrasts sharply with historical precedents where London recorded 40.2°C in July 2022, though that peak occurred at Heathrow rather than the airport station used for settlement[6]. While some YouTube forecasts predict temperatures climbing to 34–36°C during the week, the specific 24°C forecast for the airport station suggests the market is pricing in a significant divergence between city-wide heat and the localized airport reading[5].

Traders monitoring this event must watch the Met Office hourly updates for London City Airport, as the settlement relies exclusively on Wunderground data from the EGLC station[3]. The market diverges from competitors like Kalshi or Betfair in its use of implied probability (6%) rather than decimal odds, and unlike Smarkets, it operates without a traditional commission structure on the winning side[1]. For those comparing platforms, Polymarket’s KYC requirements are generally lighter than Kalshi’s US-centric mandates, while the fee structure here differs from Betfair’s spread-based model. The key catalyst remains the 12:00Z settlement cutoff, where any unrecorded spike above the forecasted 24°C would invalidate the current pricing, though current data points to a cool day relative to the city’s broader heatwave narrative[3][5].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares Highest temperature in London on July 13? 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.

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.