Highest temperature in London on July 17?

Platform comparison

Market context

London City Airport is currently cool and mostly cloudy, with temperatures at 13°C and a forecast high of just 29°C for Friday, 17 July 2026. This immediate reality explains the market’s 0% implied probability for any outcome significantly above current readings, as the day has already begun under a thick cloud layer with light air and no precipitation reported so far [1][3]. The atmosphere lacks the sustained solar heating required to push temperatures into the upper ranges traders might otherwise anticipate for mid-summer.

Historically, July is London’s warmest month, with average highs of 23°C and frequent heatwaves pushing peaks above 30°C, including the record 40.2°C at Heathrow in July 2022 [7]. However, today’s conditions diverge sharply from those scorcher scenarios; the current 0% probability aligns with the absence of a heatwave signal, as the day is statistically dry but not hot, with humidity at 88% and pressure falling [3]. Comparable cool, cloudy July days in recent years rarely exceeded 25°C, framing the current market odds as a rational reflection of the immediate weather pattern rather than a dismissal of London’s summer potential.

Traders should monitor the Met Office’s hourly updates for any sudden shift in cloud cover or wind direction, as a break in the clouds could rapidly alter the temperature trajectory before the 12:00 UTC settlement window [7]. The primary dependency is whether the “mostly cloudy” condition persists through midday, as the forecast predicts only a couple of showers later, not a temperature spike [4]. With the current high capped at 29°C and no indication of a rapid warm-up, the market’s stance remains anchored to the present outlook rather than speculative heatwave scenarios.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Prediction Today, which mirrors the Polymarket order book directly.

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

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.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

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 Prediction Today trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.