Highest temperature in Beijing on August 4?

Platform comparison

Market context

Beijing Capital International Airport is expected to sit in a typical late-summer pattern: warm to hot afternoons, humid air and a decent chance of showers or thunderstorms that can cap the day’s peak. Forecast pages for 4 August put daytime highs around the low-to-mid 30s Celsius, with one source showing about 31.5°C and others clustering around 34–36°C for Beijing more broadly, which helps explain why the market is not pricing an extreme outcome at zero and why the upper bands matter most for settlement.[1][2][3][4]

The historical frame is straightforward: August in Beijing is usually hot, muggy and rain-prone, with average highs commonly cited near 30–31°C and many guides putting typical ranges in roughly the low 20s to low 30s Celsius. That means the market should be read less as a binary on “hot or not” and more as a forecast of where the daily maximum lands within a narrow summer corridor; on a platform basis, Polymarket expresses this as share price and implied probability, while Kalshi and Betfair-style books quote in different formats, with fee treatment and access varying by venue and jurisdiction, so identical temperature views can look different in decimals, percentages and net return after costs.[5][6][11][14]

Traders should watch the same-day evolution of convective rain risk, because afternoon cloud build-up and thunderstorms are the main reasons a Beijing high can undershoot early forecasts. The key dependency is the airport-station reading on Wunderground, not the city average, so late revisions to local cloud, wind and precipitation can matter more than headline Beijing forecasts; in practice, the market’s live price should react most to whether model output continues to hold highs around 34°C or drifts down towards 31–32°C as rain chances increase.[1][12][13]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We read Highest temperature in Beijing on August 4? from four platform perspectives: Polymarket (on-chain CLOB), Kalshi (CFTC-regulated exchange), Betfair Exchange (sports book exchange), Smarkets (peer-to-peer betting exchange). Polymarket's live mid is the canonical probability; the side-by-side columns benchmark fees, KYC, settlement currency and deposit rails so you can choose the venue that fits your jurisdiction and trade size.

Resolution & payout

Polymarket settles via UMA Optimistic Oracle on Polygon. A proposer posts the outcome with a bond, the two-hour window runs, then the smart contract pays USDC.

Kalshi settles USD through the CFTC-regulated clearinghouse — the cleanest variant, with heavier KYC. Betfair Exchange settles in account currency (GBP/EUR), net of 2-5% commission. Smarkets follows the same model as Betfair with a lower default 2% commission.

FAQ

Polymarket vs Kalshi — which is better?

Depends on your location. Kalshi is CFTC-regulated, US-only with full KYC. Polymarket is global, on-chain, no KYC up to $1,500. Polymarket has ~10x higher liquidity but higher regulatory risk.

What does Polymarket cost vs Kalshi?

Polymarket: 0% fees, only Polygon network costs (~$0.01/trade). Kalshi: up to 7% per trade plus spread. For high-frequency traders, Polymarket is dramatically cheaper.

Is Betfair a Polymarket alternative?

Only partially. Betfair Exchange is UK-focused with a sports-betting emphasis; they have politics markets but with thinner liquidity than Polymarket. Settlement in GBP/EUR, 2-5% commission on winnings.

What about Smarkets as an alternative?

Smarkets is a UK betting exchange with a lower default commission (2%) than Betfair. Liquidity on political markets is below Polymarket, comparable to Kalshi. Geo-blocked in many jurisdictions.

Are all these platforms regulated?

No. Kalshi is CFTC-regulated (US). Betfair and Smarkets are UK Gambling Commission licensed. Polymarket operates without explicit regulation — a different risk profile than a regulated sportsbook.