Highest temperature in London on July 13?

Platform comparison

Market context

London City Airport is forecast to reach a high of 27°C today, with current readings at 18°C and a 20% chance of precipitation, making the 2% crowd-implied probability for a significantly higher temperature on 13 July 2026 appear conservative against typical July climatology [3][6]. Historical data confirms July is London’s hottest month, averaging 22°C, while the city’s absolute record stands at 40.2°C recorded at Heathrow in 2022, though such extremes are rare at EGLC [1][5]. The adjacent market for 14 July 2026 already assigns 47% probability to 30°C, suggesting traders view the mid-week heatwave as more likely to peak tomorrow rather than today [2].

Traders should monitor the Met Office’s hourly updates for London City Airport, as the settlement source relies exclusively on Wunderground’s daily maximum for EGLC, and any deviation in real-time readings could shift implied probabilities rapidly [3][4]. With BTC and ETH currently consolidating near key support levels, on-chain liquidity for USDC-settled weather contracts remains thin, meaning whale flows into the YES side could disproportionately impact pricing before the 12:00 UTC settlement deadline. Funding rates on crypto perps remain neutral, indicating no immediate macro catalyst to drive speculative capital into this niche weather contract, though exchange spot volume for stablecoins may rise if volatility spikes in the broader crypto market.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reads Highest temperature in London on July 13? on-chain. Polymarket's quote comes directly from the Polygon order book — the only comparable venue with on-chain settlement. Kalshi (USD, off-chain), Betfair (GBP/EUR, off-chain) and Manifold (play-money) are listed alongside for venue context. Every CTA routes to BTC Prediction, which mirrors the Polymarket order book directly.

Resolution & payout

Settlement is on-chain via UMA Optimistic Oracle. A proposer posts the outcome with a bond, a two-hour dispute window opens, then the smart contract lifts winning conditional tokens to 1 USDC and sends payments to holders' wallets automatically. No withdrawal fees beyond Polygon gas.

Off-chain venues (Kalshi, Betfair, Smarkets) settle in local fiat through bank-side clearing — faster than SWIFT, slower than on-chain. Manifold pays no real cash.

FAQ

Why USDC and not ETH or USDT?

USDC is the Polygon standard — audited reserves (Circle, monthly attestation), deepest order book, low gas costs. ETH volatility would distort probability quotes; USDT has thinner Polygon liquidity than USDC.

What does a transaction cost on Polygon?

Polygon gas is typically under $0.01 per transaction. A full trade cycle (Approve + Order + Fill) totals around $0.03 — compared to $5-50 on Ethereum mainnet.

Can I use Bitcoin directly?

No, Polymarket operates exclusively in USDC on Polygon. You can bridge BTC to USDC via an exchange or bridge service and deposit on Polygon — typically 10-30 minutes processing time.

How does UMA secure the resolution?

The UMA Optimistic Oracle uses a bond system: a proposer posts a bond, a two-hour challenge window opens. On dispute the losing side forfeits the bond — financial incentive for honest resolution.

How volatile are crypto prediction markets?

Crypto markets react to spot prices — a 5% BTC move typically shifts a "BTC above X by date" market 10-20%. Polymarket crypto market liquidity is usually six-figure USD, sufficient for active trading.