Highest temperature in London on May 28?

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Market context

London's weather on 28 May 2026 will be determined by atmospheric conditions developing over the coming weeks, with late May typically marking the transition into early summer across southern England. The 0% crowd probability suggests traders are either uncertain about the specific temperature range or awaiting clearer seasonal forecasts as the date approaches. Current meteorological patterns show typical late-spring variability, though May temperatures in London have historically ranged from highs of 24–28°C during settled periods to cooler spells around 16–18°C when Atlantic systems dominate.

Historical records from London City Airport reveal that late May temperatures rarely exceed 30°C, with the station's warmest days typically occurring in June onwards. The 1976 heatwave and more recent warm springs of 2020 and 2022 provide reference points for understanding upper-range outcomes, though these remain statistical outliers. May's average maximum sits around 19–20°C, making temperatures in the mid-20s fairly common but anything above 28°C comparatively rare for this specific date.

Traders should monitor the European summer forecast updates from the Met Office and ECMWF model runs, which typically show clearer signals by early May. High-pressure systems building from the continent would favour warmer outcomes, whilst Atlantic lows would suppress temperatures. The settlement window closes at midday on 28 May, meaning only morning and early-afternoon readings count—a constraint that slightly reduces the likelihood of capturing peak daily temperatures compared to late-afternoon measurements.

Methodology

We track Highest temperature in London on May 28? on the five venues with material liquidity for prediction markets. Live odds come from the Polymarket Polygon order book — the only source that ships real-time data under an open licence. For Kalshi, Betfair and Manifold we list platform attributes (fee, KYC, settlement, payment) instead of fabricated odds, because their APIs use non-comparable contract definitions.

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?

On Prediction Today, which mirrors the Polymarket order book at 0% fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Prediction Today 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 Prediction Today?

Zero. Prediction Today 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, Prediction Today triggers a quick verification flow that finishes in minutes.