Highest temperature in Chengdu on July 31?

Platform comparison

Market context

The underlying event is the **highest temperature recorded at Chengdu Shuangliu International Airport** on 31 July, using Wunderground’s daily history page for settlement. Chengdu’s July climate is typically hot and humid, with average daytime highs around 30–31°C and occasional days reaching the mid-30s°C, so the market is about whether today lands in the upper part of a familiar summer range rather than an extreme outlier.[2][5][8][10]

That helps explain why a **0% YES** crowd price can still be fragile: on temperature markets, odds can move sharply once the day’s realised range starts to look locked in, because the terminal outcome depends on the single highest hourly or daily observation at the airport station. Comparable July normals and historical ranges from travel and climate sources point to a broad but finite band, with typical highs near 31°C and reported July records up to about 36°C, which means late-day sunshine or a delayed rain band can still matter materially.[2][5][7][11][13]

For platform comparison, Polymarket-style pricing is usually read as an implied probability, while Kalshi and Smarkets quote tradable prices more directly in cents or decimal format, so the same view can look different once fees are added. Betfair and Smarkets also matter for access: both have broader sportsbook-style KYC and jurisdictional frictions than open crypto venues, and fee structure can change the effective break-even more than the headline probability, especially on a short-dated weather market where spreads widen into settlement.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We read Highest temperature in Chengdu on July 31? 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.