Highest temperature in London on July 16?

Platform comparison

Market context

London City Airport is set to record its peak temperature for 16 July 2026, with the outcome determining settlement for a weather contract tracking degrees Celsius. Current crowd-implied probability sits at 0% for any specific outcome, yet Polymarket data reveals a sharp divergence: the frontrunner is 28°C at 54%, followed by 29°C at 30%[1]. This stark contrast between the zero probability implied by the current listing and the active distribution on competing platforms suggests a liquidity or listing discrepancy rather than a genuine consensus on impossible conditions.

Historical mid-July highs in London typically cluster between 24°C and 30°C, making the 28°C frontrunner statistically plausible despite the 0% current tag[1]. Comparable cases from recent summers show that temperatures exceeding 29°C are possible but less frequent, aligning with the market’s secondary weighting. The absence of a meaningful probability on this specific venue, juxtaposed with the active odds on Polymarket, indicates traders should cross-reference platforms to identify the true implied distribution before settlement.

Traders must monitor real-time readings from Wunderground, the designated resolution source, as the day progresses toward the 12:00 UTC settlement window[1]. With current BBC Weather data showing 13°C and falling pressure at 2 PM UTC, the day remains cool relative to the market’s 28°C expectation[2]. No specific weather announcements are scheduled, but the primary catalyst is the hourly temperature update from London City Airport; any sudden spike above 25°C would invalidate the current 0% implication and align with the active Polymarket lines.

Sources: 1 · 2

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 Best Prediction Markets, which mirrors the Polymarket order book directly.

Resolution & payout

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

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 Best Prediction Markets. 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.

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 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.