Highest temperature in London on July 3?

Platform comparison

Market context

The real-world event at hand is the daily peak temperature recorded at London City Airport on 3 July 2026, with current forecasts pointing to a high near 26°C. While the specific prediction market in question shows a 0% implied probability for a "YES" outcome on an unspecified threshold, this diverges sharply from the broader Polymarket consensus, which assigns a 97% chance to the temperature hitting exactly 27°C and treats 26–27°C as the most likely range [1]. This stark contrast suggests a misalignment between the binary contract's pricing and the continuous temperature distribution favoured by analysts, where historical data from 2 July 2026 already recorded a maximum of 26.4°C, framing 27°C as a plausible but not guaranteed ceiling [8].

Traders should monitor the Met Office daily updates and the live Wunderground feed for any sudden shifts in cloud cover or southerly wind intensity, which are the primary catalysts for temperature spikes in this region [3][9]. The Met Office currently forecasts a daily high of 24°C for 3 July, a figure notably lower than the 26°C observed the previous day, creating a dependency on whether the current falling pressure and 88% humidity will persist or break [3][9]. Recent weather patterns indicate that July highs in London typically range between 21.8°C and 27°C, meaning the market's 0% probability for the binary outcome may be overly pessimistic if the temperature breaches the 26°C threshold seen in comparable recent days [10]. The divergence between the binary market's pricing and the continuous market's 97% confidence in 27°C highlights a critical inefficiency for cross-platform arbitrage [1].

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 Kalshi vs Polymarket, 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 Kalshi vs Polymarket. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

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.