Highest temperature in Hong Kong on August 4?

Platform comparison

Market context

Hong Kong’s weather on 4 August will settle on the Hong Kong Observatory’s highest recorded temperature for the day, and the market is currently pricing **0%** for the “YES” side despite the live board showing a broader spread of plausible outcomes. On Polymarket, the leading buckets are **30°C at 40%** and **29°C at 34%**, with **31°C at 13%** and **28°C at 12%**, which points to a market centred on the high-20s to low-30s rather than an extreme reading.[2] That profile is consistent with August climatology, where Hong Kong is typically hot and humid, but the contract’s narrow settlement bands mean small forecast errors can move the result between adjacent outcomes.[1][11]

Recent comparable cases suggest the distribution is not especially stable when local heat builds into the low-to-mid 30s. Hong Kong has already logged very warm readings this summer, including reports of the year’s hottest day reaching **34.6°C** in late July, which is a reminder that the upper tail cannot be dismissed even if the modal outcome remains around 30°C.[10][12] Against that backdrop, the 0% crowd-implied probability looks like a gap between the market title’s binary framing and the actual multi-outcome ladder: the exchange is not saying 30°C is impossible, only that the specific “YES” interpretation attached to this contract is not currently being priced as a base case.[2]

The main catalysts are the Hong Kong Observatory’s morning-to-afternoon temperature path, any thunderstorm or rain bands that cap heating, and the timing of the Observatory’s final “Daily Extract”, which will only publish after the day’s data is finalised.[3][14] The market description makes clear that settlement depends on the Observatory’s “Absolute Daily Max (deg. C)” for 4 August, so late-day warmth matters more than early readings, and the result cannot resolve until the official extract is posted.[3] For traders comparing platforms, the useful contrast is between Polymarket’s live distribution and any sportsbook-style line that may instead map the day to a single threshold; here, the crowd is clustered around 29–30°C, while the contract-specific “YES” probability remains at zero.[2]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Best Prediction Markets, which mirrors the Polymarket order book directly.

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?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Best Prediction Markets. 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.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.