Event: Highest temperature in Hong Kong on August 9, 2026. The market is a ladder of thr…

What is happening now

Polymarket traders are pricing in a high of exactly 36°C for Hong Kong on August 9, 2026, with the market implying near-certainty that the Hong Kong Observatory will record that specific maximum. The temperature ladder — spanning 11 binary contracts from “31°C or below” up to “41°C or higher” — has consolidated around the 36°C strike, where the “Yes” outcome trades at 99.3% probability. This is not a broad “hot day” bet; it is a precise call that the daily maximum will land on 36.0°C, 36.1°C, 36.2°C, 36.3°C, 36.4°C, 36.5°C, 36.6°C, 36.7°C, 36.8°C, or 36.9°C, since the resolution source measures to one decimal place.

The market is trending, with $231,909 in total volume and $197,542 traded in the last 24 hours alone, indicating fresh positioning as the resolution date approaches. The event closes at 12:00 UTC on August 9, meaning trading ends at the same moment the temperature data becomes available.

How the market is structured

This is a threshold ladder, not a single binary market. Each contract asks whether the highest temperature on August 9 falls into a specific bucket: “31°C or below,” “32°C,” “33°C,” “34°C,” “35°C,” “36°C,” “37°C,” “38°C,” “39°C,” “40°C,” or “41°C or higher.” Each bucket is a separate yes/no market, and only one can resolve to “Yes” — whichever range contains the actual recorded maximum.

The leading outcome is 36°C, with “Yes” at 99.3%. The adjacent contracts confirm this: “37°C” trades “No” at 99.4% (meaning the market is 99.4% confident the temperature will not reach 37°C), and “35°C” trades “No” at 99.95% (meaning the market is nearly certain the temperature will exceed 35°C). Together, these prices imply a tight consensus that the maximum will be 36.x°C.

Resolution depends entirely on the Hong Kong Observatory’s “Absolute Daily Max (deg. C)” figure from the Daily Extract for August 9, published at weather.gov.hk. The market cannot resolve until that data is finalized, and any revisions after initial publication are explicitly excluded.

Key outcome prices

• 36°C — Yes: 99.3% (leading outcome)
• 37°C — No: 99.4% (confirms temperature stays below 37°C)
• 35°C — No: 99.95% (confirms temperature exceeds 35°C)
• 31°C or below — No: 100% (temperature will not be cool)

Path to the leading outcome

For the 36°C outcome to resolve as the winner, the Hong Kong Observatory must record an absolute daily maximum between 36.0°C and 36.9°C on August 9. This requires a hot but not extreme summer day — consistent with Hong Kong’s climatological pattern, where August averages daily highs of 31–33°C but heat waves can push readings to 35–37°C. The Observatory’s automatic weather stations, particularly those in urban districts like Kowloon City or Tai Po, would need to log a peak in that narrow band.

Crucially, the market is already pricing this at 99.3%, meaning the implied probability is essentially locked in. For the outcome to change, the actual temperature would need to deviate significantly from this consensus — either falling to 35.x°C or lower, or climbing to 37.x°C or higher.

What could change the pricing

Several factors could shift the market away from the 36°C consensus:

• Weather model updates: If extended-range forecasts from the Observatory or international models (ECMWF, GFS) begin showing a stronger or weaker heat dome over the Pearl River Delta, the implied temperature range could shift. A forecast revision toward 37–38°C would spike “37°C Yes” and “38°C Yes” prices.
• Real-time temperature readings:

If the Observatory’s preliminary daily extract, published shortly after midnight UTC on August 10, shows a maximum outside the 36.x°C range, the market would need to settle on a different bucket. However, since the market closes at 12:00 UTC on August 9 — before the official daily extract is typically published — traders are essentially betting on forecast accuracy rather than waiting for confirmation.

• Typhoon influence: A nearby tropical cyclone could either suppress temperatures through cloud cover and wind, or enhance them through foehn effects. Hong Kong’s August weather is occasionally disrupted by typhoons, which could push readings below 35°C or, in extreme cases, above 37°C.
• Market manipulation or late liquidity: With only $1,357 in liquidity on the 36°C contract, a relatively small trade could move the price. The 24-hour volume of $52,544 on the 36°C market suggests active trading, but the thin liquidity means sharp moves are possible.