Highest temperature in Guangzhou on July 4?

Platform comparison

Market context

On 4 July 2026, the real-world event determining this market is the peak temperature recorded at Guangzhou Baiyun International Airport, measured in degrees Celsius by Wunderground. The crowd-implied probability of 0% for a specific temperature range suggests the market expects a value far outside the queried bracket, yet historical data indicates July is Guangzhou’s hottest month, with average daily highs consistently between 33°C and 35°C[2][8]. WeatherSpark confirms daily highs in July rarely dip below 35°C (85°F) or exceed 36°C (96°F), placing the typical peak firmly in the 33–35°C band[1]. This climatology frames the current 0% probability as a likely mispricing if the queried range falls below 33°C, given that even the lowest recorded July highs in recent years remain above 30°C.

A programmatically minded trader should monitor real-time Wunderground feeds and cross-reference with China Meteorological Administration alerts for heatwave announcements, as extreme temperature spikes often correlate with official warnings. Recent reports note China experienced its hottest month in recent history in July 2024, with national averages reaching 23.21°C, driven by persistent high-pressure systems[5]. For Guangzhou specifically, summer days have reached record lengths since 1961, with average temperatures climbing to 23.3°C during peak periods[7]. Traders building conditional orders must watch for scheduled updates from Wunderground at 12:00 UTC, as the settlement window closes precisely at 2026-07-04T12:00:00Z. Any sudden shift in local weather patterns, such as increased cloud cover or rain, could alter the peak temperature, but the baseline expectation remains a high of 33–35°C.

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

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 Polymarket Bot UK. 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 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.