Highest temperature in Hong Kong on June 30?

Platform comparison

Market context

Hong Kong faces a day of intense heat on 30 June 2026, with the Hong Kong Observatory forecasting maximum temperatures between 28°C and 32°C and a high probability of rain. The crowd-implied probability of 96% YES suggests traders are nearly certain the peak temperature will land within the expected range, though specific outcome markets on Polymarket show a divergence: 32°C leads at 60% while 31°C sits at 28%, indicating a tight contest between these two thresholds rather than a single dominant outcome[1].

Historical data frames this confidence, as June 2026 is forecast to deliver above-normal temperatures across the region, with the absolute maximum for June already recorded at 35.6°C in recent years[4][7]. The previous day, 29 June, saw the market assign a 100% probability to 31°C as the peak, reinforcing the pattern of consistent high temperatures in the 28–32°C band[2]. This consistency explains why the YES probability is so elevated, as the weather models and seasonal forecasts align closely with recent observational trends.

Traders should monitor the Hong Kong Observatory’s final "Daily Extract" for the absolute daily maximum, which is the definitive resolution source once data is finalized[3]. The forecast warns of a few showers and high humidity, which could suppress peak temperatures slightly below the upper 32°C limit, making the 31°C outcome a critical watch point[3]. With the settlement window closing at 12:00 UTC on 30 June, the real-time odds will shift as the day progresses and the actual temperature is recorded, so the current 60% lead for 32°C may not hold if rain intensifies[1].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Hong Kong on June 30? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

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

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'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.

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.