Lowest temperature in Hong Kong on August 11?

Platform comparison

Market context

Hong Kong’s overnight minimum on 11 August will be judged against the Hong Kong Observatory’s final “Absolute Daily Min” reading, and the market is effectively asking whether the city cools enough to print a result in the high-20s Celsius rather than the low-30s band that has dominated recent forecasts. Polymarket’s contract has been pricing a very strong lean to **29°C** at 72%, with **28°C** next at 17%, while the current 0% YES on this market implies a much harder scepticism than that venue’s distribution suggests.[8]

Seasonally, August is Hong Kong’s hottest month for night-time temperatures: the 1991–2020 daily normals put 11 August’s mean low at **26.3°C** and related August statistics point to overnight values typically around the mid-to-high 20s Celsius.[1][12] That makes a sub-27°C outcome plausible in principle, but not the base case, and it also explains why one hot-night market can swing sharply on small changes in cloud cover, rainfall and boundary-layer moisture. Past weather pages for Hong Kong show even early-morning readings that remain in the upper-20s Celsius during warm spells, reinforcing the view that the contract is mostly about whether cooling is delayed rather than whether the city turns cool in an absolute sense.[2][3]

For catalysts, traders should watch the Hong Kong Observatory’s hourly readings and any weather bulletin updates through the morning, because the relevant settlement value is taken from the published daily extract only after the data is finalised.[5][9] The HKO’s August weather records also show how quickly a wet or cloudy night can depress the minimum, but the day-ahead forecast for 11 August still pointed to a warm, humid night with showers and a high chance of continued cloud, which supports the higher-end temperature bins more than the lower ones.[10][14]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Lowest temperature in Hong Kong on August 11? 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 Kalshi vs Polymarket, which mirrors the Polymarket order book at 0% fees.

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?

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

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.