Highest temperature in Hong Kong on July 21?

Platform comparison

Market context

Hong Kong faces a day of cloudy skies with showers and thunderstorms on 21 July 2026, suppressing the likelihood of extreme heat before conditions improve mid-week. The Hong Kong Observatory’s seasonal forecast for July–September 2026 indicates temperatures will be normal to above-normal, yet today’s unsettled weather pattern directly contradicts the heat required for higher temperature brackets [1][3]. This immediate atmospheric context explains why the market currently assigns a 0% probability to any outcome above the lowest threshold, as rain and cloud cover act as a natural cooling mechanism.

Historical July data in Hong Kong typically sees daily maximums ranging between 30°C and 34°C, with 30°C being a frequent baseline during unsettled periods. The current crowd-implied probability of 0% for higher ranges aligns with the immediate forecast of thunderstorms, which historically cap temperatures near 30°C or lower [2]. Traders should note that while the seasonal outlook suggests above-normal warmth later in the quarter, the specific 21 July window is dominated by a developing low-pressure system approaching southern China, a catalyst that will keep temperatures suppressed unless the system stalls or shifts [3].

Watch for the Hong Kong Observatory’s final “Daily Extract” publication, which will confirm the absolute daily maximum once data is finalized. Any sudden shift in the low-pressure system’s trajectory could alter the settlement, but current models point to continued unsettled conditions through the weekend [3]. The market’s 99% assignment to 30°C as the frontrunner reflects this consensus, with 31°C holding only a 1% chance [2]. Traders must monitor real-time updates on the low-pressure system’s approach, as its intensity will determine whether temperatures breach the 30°C threshold.

Sources: 1 · 2 · 3

Methodology

Football-specific comparison page for Highest temperature in Hong Kong on July 21?. Polymarket's live quote (Polygon order book) plus platform attributes for the three reference venues. Sports markets reward liquidity — Polymarket and Betfair are materially deeper than Kalshi (US-focused) or Manifold (play-money).

Resolution & payout

Sports markets typically settle on official final-whistle plus league confirmation. Polymarket uses UMA Optimistic Oracle with a source URL per contract — usually official league data feeds or ESPN/Soccerway. Two-hour dispute window, then smart-contract payout in USDC.

FAQ

Are prediction markets better than sports betting?

Prediction markets tend toward tighter odds than bookmakers because they use peer-to-peer exchange rather than bookmaker margin. On major matches, Polymarket quotes typically sit 2-5% closer to the true probability model than bet365 or DraftKings.

When do sports markets resolve?

Typically within hours of the official final whistle. Polymarket uses UMA Optimistic Oracle with source URLs pointing at official league data feeds — e.g. the Premier League for EPL markets, UEFA for Champions League, FIFA for World Cup.

Can I bet on individual matches?

Yes, Polymarket lists every major Premier League / Champions League / World Cup match as its own market. Liquidity varies — top matches like El Clásico or a semi-final often have six-figure pools, lower-league games closer to three-figure.

Which sports markets are available?

Football (soccer) dominates — Champions League, World Cup, Premier League, La Liga, Bundesliga — followed by NFL, NBA, tennis Grand Slams, Formula 1, boxing/MMA. Resolution via official league source confirmation.

What's the difference between match odds and outright odds?

Match odds cover a single game ("Bayern beats BVB"). Outright odds are long-term aggregates ("Bayern wins the league"). Outright markets have deeper liquidity; match markets have faster resolution.