Highest temperature in London on July 17?

Platform comparison

Market context

London City Airport is set to record its highest temperature for 17 July 2026, a single data point that will settle a conditional token contract on Polygon. Today, the market prices the chance of the temperature falling between 80–81°F (roughly 26.7–27.2°C) at 0% YES, implying traders expect the peak to sit outside this narrow band. Settlement hinges on the Wunderground daily history for EGLC, with USDC payouts executed automatically once the 2026-07-17T12:00:00Z window closes.

Historical July peaks at London City Airport often exceed 27°C during heatwaves, with 2022 and 2023 both recording highs above 30°C at nearby stations, though EGLC typically reads slightly cooler due to its riverine location. The current 0% probability suggests the crowd anticipates either a significantly cooler day or a spike well beyond 27.2°C, mirroring past volatility where mid-July highs swung by 5–7°C within a week. Traders should note that EGLC’s 2024 July average peaked near 24°C, making the 80–81°F range plausible only under stable, non-extreme conditions.

Key catalysts include the Met Office’s 7-day forecast for London, which updates daily and may signal an approaching high-pressure system from the continent. A recent BBC Weather update for London City Airport shows current conditions at 13°C with falling pressure, but this is irrelevant to the July 2026 event; instead, watch for the Met Office’s mid-July 2026 outlook, expected to publish by early July, as it will define the thermal trajectory. Any sudden shift in the North Atlantic Oscillation could act as the decisive trigger for temperature extremes.

Sources: 1 · 2

Methodology

This page reviews Highest temperature in London on July 17? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to PolyGram, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

FAQ

Where can I trade this market with the lowest fees?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is PolyGram. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

What's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like PolyGram trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.