Highest temperature in Shanghai on June 21?

Platform comparison

Active sub-markets

Market context

Shanghai’s airport temperature will be set by the highest reading at Pudong Airport before the settlement cut-off, so the key question is whether the day stays in the high-20s Celsius or pushes into an unusually warm spike. BBC Weather for nearby Hongqiao shows thundery showers and a forecast high of 28°C on 21 June, while WeatherSpark’s June climatology for Pudong puts typical daily highs around 77–83°F, with rare extremes above 92°F, so the current 0% YES price is consistent with a market expecting no break-out heat.[1][2]

For comparison across venues, the same underlying weather event would usually trade more cleanly on Polymarket and Kalshi because each contract resolves to a binary or banded outcome, whereas a venue like Betfair would express the view through decimal odds and Smarkets through commission-adjusted back and lay prices, making the same forecast look different on screen even when the implied probability is similar. The practical implication is that fee drag, spread, and any local KYC limits matter more on a low-volatility weather market: when the expected temperature sits close to the lower range bands, small differences in fees or access can outweigh the signal itself, especially for traders seeking only a marginal edge.[2][3]

The main catalysts are the live Shanghai conditions through the afternoon and any rapid shift in convection, because thundery showers can suppress the day’s maximum even if humidity is high. The relevant settlement source is Wunderground’s Shanghai Pudong International Airport Station history page, and the market closes before the UTC day ends, so traders need to watch the intraday high rather than the overnight forecast; at 08:00 UTC, the BBC forecast already suggests unsettled weather rather than a heat-driven outcome.[1][4]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We read Highest temperature in Shanghai on June 21? 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 quote comes directly from the Polygon order book; the other three are listed with their platform attributes — fees, KYC, settlement currency, payment options — because a 1:1 contract comparison without API access would be guesswork.

Resolution & payout

Settlement is the biggest difference between the four platforms: Polymarket on-chain in USDC (instant), Kalshi USD via CFTC (T+1), Betfair and Smarkets in local currency via bank withdrawal (T+1 to T+3). Kalshi Alternative UK routes every trade directly into Polymarket's on-chain settlement, which is why payouts land fastest.

FAQ

Where can I trade this market with the lowest fees?

On Kalshi Alternative UK, which mirrors the Polymarket order book at 0% 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.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, Kalshi Alternative UK triggers a quick verification flow that finishes in minutes.

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.