Highest temperature in Hong Kong on May 25?

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Active sub-markets

Market context

On 25 May 2026, the Hong Kong Observatory will record the day's maximum temperature in degrees Celsius. This market resolves to whichever temperature band contains that single data point, drawn from the Observatory's official daily climate extract once finalised. The settlement window closes at midday UTC on that date, though resolution itself depends on the Observatory publishing verified data, which typically occurs within days of observation.

Hong Kong's May temperatures cluster predictably around 28–32°C, with extremes rare but documented. Historical May maxima range from 24°C in cooler years to 35°C during heat waves, though readings above 33°C occur roughly once per decade in this month. The 0% crowd probability suggests either no active traders or genuine uncertainty about which specific band will resolve. For programmatic traders, this presents a calibration problem: the market's outcome is deterministic once the date passes, yet current odds reflect no consensus on distribution. Comparing adjacent May datasets from 2015–2025 provides the baseline; anomalous patterns (El Niño persistence, tropical cyclone proximity) shift the tail probabilities materially.

Traders monitoring this market should track the Hong Kong Observatory's seasonal forecasts and any tropical cyclone activity in the Western Pacific during late May 2026. The Observatory publishes monthly outlooks; deviations from the 30-year May average signal whether conditions favour cooler or warmer extremes. Conditional order logic could automate position sizing once May forecasts solidify, roughly four weeks before settlement. The key dependency is data availability—the Observatory's publication schedule determines when resolution becomes possible, not the market's closing time.

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

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

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.

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'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.

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.