Highest temperature in London on July 23?

Platform comparison

Market context

London City Airport’s reading on 23 July will mostly be a weather story, not a political one: the market settles on the **day’s maximum temperature** at EGLC, and the key question is whether the station ever produces a spike high enough to matter before the midday settlement cut-off. Wunderground’s daily history page is the resolving source, so intraday warmth, cloud cover, wind off the Thames, and the timing of any brief convective burst are the only real drivers of the final print.

The current **0% YES** implies the crowd is not pricing in an exceptional London heat event. That fits the broader climate record, where London’s all-time high is **40.2°C**, set during the July 2022 heatwave at Heathrow and St James’s Park, with the Met Office describing those days as unprecedented for the UK in both intensity and duration.[2][3][4][5] For a summer daily-temperature market like this, the relevant comparison is not the record itself but the long tail of hot July afternoons: a single outlier reading can still settle the contract even if the day is otherwise ordinary.

Traders should watch the same catalysts forecasters use for short-range temperature swings: Met Office updates, any hot-air advection from continental Europe, and the morning cloud/rain forecast that can cap the daytime peak. The market is leaning on *meteorological setup* rather than a scheduled event, but overnight and early-morning guidance matters because the settlement window ends at **12:00 UTC**, leaving only the first part of the day to register the maximum; once that window closes, later afternoon heat will not change the outcome.[1]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page tracks Highest temperature in London on July 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. For users geo-blocked from Polymarket directly, brokers like Trump Prediction provide a 0%-fee route into the same order book.

Resolution & payout

For political markets the resolution source is decisive. Polymarket defines a concrete source per contract (e.g. AP, Reuters, official electoral commission) and uses the UMA Optimistic Oracle as the on-chain dispute mechanism. With a clearly defined outcome the USDC payout lands within minutes of the final confirmation.

FAQ

How accurate are political prediction markets?

Historically more accurate than polls. Polymarket's Brier score on US 2024 elections was ~0.11 — better than 538 (~0.14) and every mainstream poll. Markets aggregate information with real skin in the game.

What resolution source is used for elections?

Polymarket defines the source per contract — usually Associated Press (AP Race Call), Reuters or the official electoral commission. The source is stated in contract details before the market opens.

Can prediction markets influence election outcomes?

Markets reflect expectations rather than create them. Studies show public-facing markets can anchor expectations, but don't influence the underlying outcome. Political markets are information, not advocacy.

Which platform has the deepest political liquidity?

Polymarket — by far. US 2024 presidential volume was ~$3.5B vs Kalshi (~$200M) and Betfair (~$120M). Where Polymarket is geo-blocked, brokers like Trump Prediction route into the same order book at 0% fees.

How fast do political markets react to news?

High-liquidity markets move within seconds to minutes. A Trump tweet on the economy can shift the "Trump 2024" market 2-5 points before mainstream media has written anything.