Highest temperature in Shanghai on August 9?

Platform comparison

Market context

Shanghai’s reading will be set by the **highest temperature** in Weather Underground’s Daily Observations for Shanghai Pudong International Airport Station, not the headline “Day High & Low” figure, so intraday spikes matter more than the summary display. Current forecasters expect a warm but unsettled August day, with Shanghai forecasts around the upper 20s to mid-30s Celsius and a high chance of rain or thunderstorms on 9 August, which tends to cap sustained heat even when humidity stays high.[5][7][13][14]

The 0% crowd-implied probability is useful as a signalling point, but it does not mean a cold outcome; rather, it may reflect thin trading, uncertainty around the exact Weather Underground observation series, or a market that has not repriced yet. Comparable August climatology still leaves room for a mid-30s Celsius print in Shanghai, since published monthly averages commonly put daytime highs around 31–34°C and some sources show daily forecast highs near 34–35°C even with rain in the area.[1][6][9][16] On Polymarket, the quoted figure is typically an implied probability, while Kalshi and Betfair-style books present prices differently, and Smarkets adds a commission layer that changes the effective break-even versus the displayed odds; KYC access also varies by venue, which can affect who is able to trade this kind of weather contract.

The main catalysts are the evolving local forecast and the timing of any rain bands, because a wet morning can suppress the day’s ceiling while a brief sunny window can still produce the settlement high. Traders should watch late updates from forecasters such as AccuWeather, Time and Date, and China Weather sources, as their 9 August outlooks already differ on whether Shanghai peaks closer to 28–29°C or the mid-30s, a gap that matters for which settlement band ultimately wins.[5][7][14]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares Highest temperature in Shanghai on August 9? specifically across Polymarket, Kalshi, Betfair Exchange and Smarkets. The live probability is the Polymarket mid; the comparison columns summarise each venue's fee structure, KYC, settlement currency and payment rails. Every CTA routes to Kalshi Alternative, which mirrors the Polymarket order book at 0% fees.

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.

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.

Which platform supports Klarna/SOFORT?

Directly: none. Polymarket accepts only USDC on Polygon. Kalshi Alternative offers a fiat on-ramp via Klarna or SOFORT (DE/AT/CH) and converts internally to USDC for the Polymarket order book. T+1 processing.