Highest temperature in Hong Kong on July 21?

Platform comparison

Market context

On 21 July 2026, Hong Kong will record its peak daily temperature, a figure that the Hong Kong Observatory will publish as the absolute daily maximum in degrees Celsius. The market currently prices a YES outcome at 0%, implying the crowd believes the temperature will fall outside the offered range, likely viewing the bracket as too high for typical midsummer conditions in the city.

Historically, Hong Kong’s July highs cluster between 31°C and 34°C, with extreme spikes above 35°C occurring only during prolonged heatwaves under weak monsoon flow and clear skies. The last time the city breached 36°C was in August 2022, while July 2023 peaked at 33.8°C. Given the 0% implied probability, the consensus treats the range as an underdog scenario; value may sit on a contrarian bet if tropical cyclone activity or a strong subtropical ridge pushes temperatures toward the upper historical tail, though such events remain statistically rare for this date.

Traders should monitor the Hong Kong Observatory’s daily weather bulletins and the China Meteorological Administration’s tropical cyclone warnings, as an approaching system could suppress temperatures, while a persistent high-pressure cell might drive them up. Recent forecasts from the Observatory’s July 2026 seasonal outlook suggest above-average temperatures but no confirmed heatwave, leaving room for volatility if a sudden ridge strengthens over the next fortnight [1]. The settlement hinges entirely on the final “Daily Extract” published after 12:00 UTC on 21 July, so real-time updates from the Observatory’s website will be the sole catalyst for price movement.

Methodology

This page reviews Highest temperature in Hong Kong on July 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 Who Will Win 2026, 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

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Who Will Win 2026 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.