Lowest temperature in Hong Kong on July 31?

Platform comparison

Market context

Hong Kong’s lowest temperature on 31 July will be set by the Hong Kong Observatory’s daily extract, not by any private weather desk, so the contract is effectively a bet on the morning minimum finishing inside one Celsius range. The crowd-implied 3% YES points to a view that the day’s floor will land in a relatively unlikely bracket, while the reference source explicitly settles on the Observatory’s “Absolute Daily Min” to one decimal place, which means the exact cut-offs matter more than broad “cool” or “hot” descriptors.

Historically, July in Hong Kong is warm through the night as well as the day, with typical lows around 27°C to 28°C and monthly record minima clustered in the high 27s; the Observatory’s July ranking shows the coldest July minimum on record at 27.7°C, with several other top readings at 27.6°C to 27.3°C.[2] That framing makes a materially low outcome uncommon in a normal July, and the market’s 3% pricing is broadly consistent with the idea that a sub-27°C print would need unusual overnight rain, cloud cover, or a weather-system change. Comparable case data also show that isolated synoptic events can pull the minimum sharply lower: on 31 July 2019, the Observatory reported 24.5°C amid heavy rain from Wipha’s outer rainbands.[4]

The main catalyst is the Observatory’s final daily extract, which may lag the end of the settlement window and can only resolve once published.[15] Traders should watch the hourly readings and any late-day rainfall or thunderstorm coverage from the Observatory’s public updates, because a wet, cloudy night can suppress the minimum more than the broader monthly average suggests.[7][18] There is no sportsbook benchmark in the sources provided, so the cleanest comparison here is between the prediction-market price and the weather-history consensus: both imply a low-probability tail event rather than a routine July minimum.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Lowest temperature in Hong Kong on July 31? 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 Best Prediction Markets, 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

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.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Best Prediction Markets 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.