Highest temperature in Guangzhou on July 7?

Platform comparison

Market context

The underlying real-world event is the highest temperature recorded at Guangzhou Baiyun International Airport on 7 July 2026, measured in degrees Celsius. Today, Polymarket prices the YES contract for a 34°C peak at 0% despite historical July averages near 32–33°C and daily highs rarely falling below 85°F (29.4°C) or exceeding 96°F (35.6°C)[3]. This zero valuation suggests the market treats a 34°C outcome as virtually impossible, yet comparable data from 3 July 2026 shows a 34°C peak resolved as YES with a 27.5% implied probability, indicating traders previously estimated a one-in-four chance for that exact temperature[1]. Such variance frames the current 0% price as an outlier when weighed against typical summer volatility where hotter outcomes like 35°C or cooler readings like 32°C remain plausible[1].

Traders must monitor the official weather schedule for Guangzhou, specifically the release of daily high temperatures from Wunderground, which serves as the definitive resolution source for this market[6]. Recent reports confirm that many places in China have experienced heat waves this summer, with Guangzhou’s average July temperature reaching 23.2°C, the highest since 1961, suggesting elevated thermal conditions that could shift probability away from zero[4]. Additionally, the settlement window ends at 12:00 UTC on 7 July 2026, requiring on-chain USDC trades on Polygon to be executed before this deadline to capture conditional token payouts if the temperature deviates from current expectations[5]. The dependency on Wunderground data means any delay or anomaly in the reported daily high could directly impact the final resolution outcome.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

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

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 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.