Highest temperature in London on August 8?

Platform comparison

Market context

Polymarket is pricing this contract at **100% for 28°C**, with the position settled in USDC on Polygon through conditional tokens, so the market is effectively treating the outcome as already locked in. That matters because the contract resolves off the **highest temperature in Weather Underground’s Daily Observations table** for London City Airport Station on 8 August 2026, not the summary “Day High & Low” figure, and revisions count only until the first datapoint for the next date appears.[1]

For context, the current read sits in line with how recent London temperature markets have behaved when forecasts and observations converge early: Polymarket’s London temperature contract for 6 August resolved at **23°C** after the Heathrow-based daily maximum confirmed the bracket, showing that these markets can settle decisively once the reporting station’s table is complete.[18] In the present market, the crowd has pushed everything into a single outcome, leaving **0%** assigned to the lower bands and suggesting traders have either already seen the station-level data or are discounting any late adjustment from Weather Underground.[1]

A trader still watching the tape would focus on whether the London City Airport observations page has published the final 8 August entries and whether any post hoc correction appears before the next day’s first datapoint, since that is the only window in which the resolved band could change.[1] The broader weather backdrop also matters: the UKHSA had a **yellow heat-health alert** in force for London from 8 August, indicating conditions were warm enough to keep forecasters and data-watchers attentive to any late-day peak near the top of the current bracket.[11]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in London on August 8? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to PolyGram, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like PolyGram 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.