Highest temperature in London on June 23?

Platform comparison

Active sub-markets

Market context

The underlying event is the peak daytime temperature recorded at London City Airport on 23 June 2026, with current markets assigning a 98% probability that the figure will fall within the expected range. Historical data shows that late June in London typically sees highs between 23°C and 28°C, though recent years have experienced spikes above 30°C during heatwaves. The Met Office notes that the warm season begins mid-June, with average daily highs exceeding 19°C, but extreme days can breach 33°C under sustained southerly flow [5][6].

Traders should monitor real-time forecasts from AccuWeather and Wunderground, which currently predict a sweltering 33°C (93°F) for 23 June, citing “brilliant sunshine” and dangerous heat conditions [2][3]. The market is leaning on the forecasted high-pressure system moving in from the south, which aligns with recent patterns of record-breaking June temperatures. A sudden shift in wind direction or cloud cover could alter the outcome, but current signals strongly support the 98% YES position. No political or campaign-finance catalysts are relevant here; the sole driver is meteorological [9].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page tracks Highest temperature in London on June 23? across four political prediction venues. Live odds come from the Polymarket order book (the deepest political prediction-market book). Kalshi is the CFTC-regulated US alternative, Betfair the established UK sports-exchange with politics markets, Manifold the open play-money variant. Trump Prediction routes every trade through to Polymarket — at 0% fees.

Resolution & payout

Political markets typically settle on official candidate or agency confirmation. Polymarket uses UMA Optimistic Oracle: a proposer posts the outcome with a bond, the two-hour window opens, then the smart contract pays USDC.

Kalshi settles USD via CFTC clearinghouse, with clearly defined resolution sources (e.g. AP race calls for elections). Betfair settles after the official outcome is registered with the league or agency. Manifold is play-money.

FAQ

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

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 it cost to trade on Trump Prediction?

Zero. Trump Prediction routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

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.