Highest temperature in Guangzhou on July 20?

Platform comparison

Market context

Guangzhou will experience its peak daytime heat on 20 July 2026 at the Baiyun International Airport station, with the market resolving to the Celsius range containing that daily maximum. The current 0% YES probability implies the crowd expects the temperature to fall outside the specific range offered, a stance that contradicts typical mid-summer climatology for the region where July highs routinely exceed 30°C.

Historical data from the same station shows July 2025 recorded a high of 34°C, while the decade average for mid-July in Guangzhou sits between 32°C and 35°C [1]. Programmatic traders should treat the 0% figure as a potential mispricing error rather than a genuine forecast of cold weather, as the settlement relies on Wunderground’s official daily maximum, which rarely dips below 30°C in this window. A script monitoring the live Wunderground history feed for ZGGG would flag this divergence immediately, comparing the live 34°C+ trend against the implied zero probability.

Traders must watch the hourly meteorological updates from the China Meteorological Administration for any sudden rain fronts or cloud cover that could suppress temperatures below the expected range. While no specific announcements are pending, the dependency on the 12:00 UTC settlement cut-off means the final hour of local afternoon heat (around 19:00–20:00 local time) is the critical catalyst. Automated bots should ingest the real-time Wunderground stream to verify if the recorded high breaches the market’s upper threshold before the clock strikes, ensuring the conditional order executes only on confirmed data.

Sources: 1

Methodology

This page reviews Highest temperature in Guangzhou 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 Fees, which mirrors the Polymarket order book at 0% fees.

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.

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.