Highest temperature in London on June 4?

Platform comparison

Active sub-markets

Market context

On 4 June 2026, the highest temperature recorded at London City Airport will fall into one of several defined ranges. The settlement hinges on data from Weather Underground's historical records for that specific station, which sits in East London and typically captures conditions representative of central London's urban heat island effect. The 0% crowd probability suggests traders currently see no conviction in any particular range, or the market has attracted minimal liquidity relative to competing weather books.

London's June temperatures typically range from 18–24°C, though heat waves can push readings into the high 20s. The Met Office's seasonal outlook and any European high-pressure systems developing in late May will be critical signals. Recent precedent: June 2022 saw London reach 32°C during an exceptional heatwave, whilst June 2023 remained cooler at around 21°C average highs. Traders comparing this market across platforms should note that Polymarket's binary or range-based structure differs from Kalshi's categorical approach; Betfair and Smarkets offer decimal odds that may price tail-risk ranges differently depending on their respective user bases' weather expertise.

The settlement window closes at midday on 4 June 2026, giving traders roughly four days of real-time weather forecasting before resolution. The Met Office's extended forecast and European weather models (ECMWF) will sharpen predictions in the final 72 hours. Any sudden atmospheric blocking pattern or jet-stream repositioning announced in late May could shift implied probabilities sharply across all platforms, though fee structures and liquidity depth will determine execution costs for late movers.

Methodology

We read Highest temperature in London on June 4? from four platform perspectives: Polymarket (on-chain CLOB), Kalshi (CFTC-regulated exchange), Betfair Exchange (sports book exchange), Smarkets (peer-to-peer betting exchange). Polymarket's live quote comes directly from the Polygon order book; the other three are listed with their platform attributes — fees, KYC, settlement currency, payment options — because a 1:1 contract comparison without API access would be guesswork.

Resolution & payout

Settlement is the biggest difference between the four platforms: Polymarket on-chain in USDC (instant), Kalshi USD via CFTC (T+1), Betfair and Smarkets in local currency via bank withdrawal (T+1 to T+3). Polymarket Alternative routes every trade directly into Polymarket's on-chain settlement, which is why payouts land fastest.

FAQ

Is this market available outside the US?

Polymarket Alternative is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

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 does it cost to trade on Polymarket Alternative?

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

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, Polymarket Alternative triggers a quick verification flow that finishes in 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.