Highest temperature in London on August 2?

Platform comparison

Market context

Polymarket is currently pricing the *exact* London City Airport high for 2 August in USDC on Polygon, with the market showing 0% for a 0% YES-style framing because traders are still waiting for the day’s observed maximum to settle into one of the Celsius bands. The contract resolves to the range containing the highest temperature recorded at London City Airport Station on the day, using Wunderground as the source of truth, so the key live question is whether the airport’s official high lands in the mid-20s or edges into the upper-20s before the noon UTC settlement window closes.

The read-through from comparable summer days is straightforward: when south-east England is under high pressure, the market tends to migrate towards the warmer bands quickly, but London City Airport can still underperform central London in a marginal setup because onshore flow and cloud cover blunt the peak. Current Polymarket pricing is anchored by a 27°C frontrunner at 52% and 26°C at 26%, with 28°C a live outsider, which fits a forecast profile of warm but not necessarily exceptional conditions. Recent UK heat coverage has also shown how quickly traders reprice when official forecasts firm up or when a heat alert is upgraded, especially after the Met Office has flagged sustained warmth in southern England.

A trader watching this market should focus on the morning forecast updates, the airport’s hourly observations, and whether the synoptic pattern holds long enough for the day’s maximum to be registered before the market’s settlement cut-off. London summer highs can shift materially if cloud breaks arrive late or if a southerly feed strengthens, and that matters because the final outcome is tied to the recorded maximum, not an inferred city-wide temperature. On Polymarket, the winning band settles via conditional tokens redeemable for $1 each, so any change in the expected peak near midday UTC can move implied odds sharply as the first definitive readings come through.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in London on August 2? 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 Kalshi UK, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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 UK. 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.

Do I need to KYC for this market?

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