Highest temperature in Guangzhou on July 21?

Platform comparison

Market context

Guangzhou’s highest temperature on 21 July 2026 will be recorded at the Baiyun International Airport Station and resolved via Wunderground’s daily history. The market currently shows a 0% crowd-implied probability for the YES outcome, yet Polymarket data indicates the frontrunner is 31°C at 90%, with 32°C at 9% [2]. This discrepancy suggests the YES condition likely targets a specific threshold above the typical July range, where historical highs average 32°C (90°F) and lows sit near 25°C (78°F) [4].

Programmatic traders should model this using historical Wunderground series for ZGGG, filtering for 21 July entries across the past decade to identify outlier days. Comparable cases show July in Guangzhou is consistently hot, with wind speeds averaging 17.4 kph and humidity often exceeding 90%, which can suppress peak temperatures despite high RealFeel readings [1][4]. A 0% probability on YES implies the threshold is set above the 90th percentile of observed highs, making it a low-probability bet unless an extreme heat anomaly occurs.

Key catalysts include real-time weather bulletins from AccuWeather and local meteorological updates, as sudden shifts in cloud cover or rain can alter the peak. Current conditions show light rain and fog, which may cap the day’s maximum below the threshold [3]. Traders should monitor the 12:00 UTC settlement cutoff and verify Wunderground’s final entry, as conditional orders can be triggered by live temperature feeds if the platform supports API integration. No official announcements are expected, but regional heat advisories could serve as early signals.

Sources: 1 · 2 · 3 · 4

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Kalshi Fees, which mirrors the Polymarket order book directly.

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

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Kalshi Fees trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

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.