Highest temperature in London on July 16?

Platform comparison

Market context

London City Airport is recording 13°C today, a cool start for mid-July that aligns with the market’s 0% implied probability for any extreme heat outcome. Historical data for London in mid-July typically shows highs between 18°C and 24°C, with record highs rarely exceeding 30°C unless a rare heatwave occurs. The current crowd sentiment suggests traders see no chance of temperatures reaching the upper thresholds defined in the market’s resolution ranges, likely due to the prevailing cool, humid conditions and falling pressure noted by BBC Weather[2].

Traders comparing Polymarket to Kalshi, Betfair, or Smarkets should note that Polymarket displays outcomes as implied probabilities rather than decimal odds, and operates without KYC for most users, unlike the regulated UK books. Fee structures also diverge: Polymarket charges a small trading fee on profit, while Smarkets and Betfair apply commission on winnings or take a spread. On this specific weather market, the 100% probability assigned to the 74–75°F range (23.3–23.9°C) on Polymarket contrasts with the 0% on the lower range, highlighting how platform framing can skew perceived risk[1]. No new announcements or weather forecasts are expected to shift this before settlement on 16 July 2026 at 12:00 UTC.

Sources: 1 · 2

Methodology

We read Highest temperature in London on July 16? from four platform perspectives: Polymarket (on-chain CLOB), Kalshi (CFTC-regulated exchange), Betfair Exchange (sports book exchange), Smarkets (peer-to-peer betting exchange). Polymarket's live mid is the canonical probability; the side-by-side columns benchmark fees, KYC, settlement currency and deposit rails so you can choose the venue that fits your jurisdiction and trade size.

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

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.

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.

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. Robinhood Prediction Markets 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.