Highest temperature in Hong Kong on August 21?

Platform comparison

Market context

Hong Kong Observatory readings on the morning of 21 August showed 27°C at 8 a.m., with light rain and widespread inland temperatures in the mid-20s, which points to a softer intraday setup than the very hot spells seen earlier in the month[1]. That matters because this contract settles on the day’s absolute maximum in Celsius, so the market is really about whether the afternoon rebound can clear the low-30s rather than the early-morning reading.

The current 0% yes price looks much lower than the wider temperature picture. AccuWeather’s August outlook has Hong Kong’s daily highs mostly in the high-20s to low-30s Celsius, while recent Observatory notices have repeatedly flagged Very Hot Weather conditions in the territory this month[2][3]. Against that backdrop, a 0% implied probability suggests the market is pricing an outcome below even a modest daytime rise, and that is notably tighter than the broad forecast range.

For traders, the key catalyst is the Observatory’s final Daily Extract, because the market cannot resolve until the Absolute Daily Max for 21 August is published. Intraday swings in cloud, rain, and any renewed heat warning are the main dependencies, with the morning bulletin already showing rain at several locations and no strong pre-noon heat surge[1]. The closest comparable read-through is the recent pattern of official hot-weather warnings followed by sharply varying district highs, which leaves the final published maximum more important than early-session conditions[1][3].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in Hong Kong on August 21? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to PolyGram, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

FAQ

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

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?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like PolyGram trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

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.