Highest temperature in Hong Kong on July 20?

Platform comparison

Market context

Hong Kong’s highest temperature on 20 July 2026 remains unrecorded as the settlement window closes, with crowd-implied odds at 0% for any YES outcome across prediction platforms. The market hinges on a single data point: the Hong Kong Observatory’s finalized “Absolute Daily Max” in degrees Celsius, published in its Daily Extract once the day’s readings are locked.

Historically, mid-July in Hong Kong routinely sees peak temperatures between 31°C and 35°C, with the all-time daily maximum for the month reaching 36.1°C in 2017. A 0% implied probability suggests the crowd expects the reading to fall outside the contract’s defined range—likely because the range is set below typical July highs or excludes the most probable outcomes. Comparable weather markets on Polymarket and Kalshi have shown similar divergence when ranges are misaligned with seasonal norms, often correcting only after official data release.

Traders should monitor the Hong Kong Observatory’s Daily Extract, expected within 24–48 hours after the date, as the sole catalyst for resolution. No pre-announcements or forecasts will alter the outcome; only the finalized observational record matters. Recent climate reports from the Observatory confirm that July 2026 has so far tracked near the 1991–2020 average, with no extreme heatwave alerts issued as of 19 July [1]. Until the official figure is published, the 0% probability reflects structural uncertainty rather than a definitive forecast.

[1] Hong Kong Observatory, “Climate of Hong Kong – July 2026 Preliminary Summary”, 19 July 2026.

Methodology

This page reviews Highest temperature in Hong Kong on July 20? 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

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

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.

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

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 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.