Highest temperature in Chengdu on August 20?

Platform comparison

Market context

On 20 August 2026, the highest temperature recorded at Chengdu Shuangliu International Airport will determine this market's resolution. The settlement window closes at midday UTC, meaning traders must rely on overnight data feeds from Weather Underground's Daily Observations table—the specified source, distinct from the platform's summary high-low display. This technical distinction matters: discrepancies between observation-level and summary-level reporting have historically created settlement disputes on weather markets across platforms.

Chengdu's August climate sits in the tail end of its summer monsoon season, with historical highs typically ranging 29–35°C. The 0% crowd probability suggests either extreme confidence in a specific temperature band or insufficient liquidity to establish meaningful odds. Comparable August readings from 2015–2024 show considerable year-to-year variance; the city experienced a 37.2°C peak in August 2022 but only 33.1°C in 2019. Traders should examine Wunderground's station-specific historical data rather than city-wide averages, as airport microclimates often diverge from urban centres.

The critical dependency is data availability on settlement day. Unlike Kalshi's automated weather feeds or Betfair's manual resolution processes, Polymarket relies on user-submitted Weather Underground links, creating potential delays if the station's overnight upload lags. Smarkets and other European books typically close weather markets earlier to avoid such friction. Traders should verify Wunderground's Chengdu station operational status now; airport weather stations occasionally undergo maintenance. Any disruption to data transmission between 20–21 August could trigger resolution delays or appeals, particularly if the recorded high falls near a range boundary.

Methodology

We read Highest temperature in Chengdu on August 20? 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.

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.

Which platform is accessible globally?

Polymarket is geo-blocked in the US/UK/EU. Kalshi is US-only. Betfair and Smarkets are UK-restricted. Polymarket Alternative has a different geo footprint and routes to Polymarket's order book at 0% fees.

Which platform supports Klarna/SOFORT?

Directly: none. Polymarket accepts only USDC on Polygon. Polymarket 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.