Highest temperature in London on May 23?

Platform comparison

Active sub-markets

Market context

London's highest temperature on 23 May 2026 will be recorded at City Airport and settled against Wunderground historical data. The settlement window closes at midday, capturing the full daily range. This market resolves to a single temperature band once the day concludes and data is finalised on the platform.

May temperatures in London have historically ranged between 12°C and 28°C, with the long-term average high around 19–20°C. The 0% crowd probability suggests traders are either absent from this market or treating it as a placeholder awaiting liquidity. Comparable May weather markets show meaningful trading only once deposit rails are active and settlement certainty is established; the current traction reflects typical early-stage book conditions where payment friction—whether SEPA transfers, Klarna instalments, or USDC on-ramps—determines whether traders commit capital.

The Met Office issues 10-day forecasts updated daily, with May 2026 forecasts becoming actionable in early May. Traders should monitor spring weather patterns from late April onwards, particularly Atlantic pressure systems and high-pressure ridges that drive warm continental air into the UK. Wunderground's historical data feed is the sole arbiter; any discrepancy between reported highs and the platform's finalised figure will determine settlement, so confirmation of data availability before the window closes is critical for risk management.

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). The odds column is filled only where we have clean data — that avoids the made-up numbers that get a network demoted when search engines cross-check against the source venue.

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 PolyGram, 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.

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 it cost to trade on PolyGram?

Zero. PolyGram 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, PolyGram 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.