Highest temperature in Beijing on August 8?

Platform comparison

Market context

Beijing’s outcome here depends on the *single highest hourly reading* at Beijing Capital International Airport on 8 August, as captured in Weather Underground’s **Daily Observations** table rather than any summary high-and-low box. For a programmatic trader, that means polling the station history page, extracting the day’s maximum temperature in °C, and mapping it to the market’s settlement bands rather than relying on a forecast widget or a rounded daily headline.[17]

The 0% YES print is consistent with how August temperature markets usually behave before the day has fully played out: the final number is often set by a brief afternoon spike, not the morning level. Beijing’s August climate is typically hot, with long-run averages around 30–31°C and historical highs commonly reaching the mid-30s °C, so the relevant question is not whether it will be warm, but whether the day’s peak lands inside the band the market has priced out entirely.[3][6][14]

The practical catalysts are the weather cycle itself and the source update cadence. In Beijing, the decisive move usually comes around local afternoon heating, so traders watching conditional orders or bot-triggered entries will want to check the Wunderground station page through the day and confirm whether a later observation exceeds earlier readings.[1][17] For a weather contract, there is no separate policy or event calendar dependency beyond the live station record, but the key operational risk is source mismatch: if the Daily Observations table updates after a summary view, the table controls settlement.[17]

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

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 Kalshi Fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.