Highest temperature in Sao Paulo on July 9?

Platform comparison

Market context

The highest temperature recorded at São Paulo-Guarulhos International Airport on 9 July 2026 will determine this market’s outcome, with the contract currently pricing a 23°C hit at 43% and a 22°C result at 98% on Polymarket. Traders using USDC on the Polygon network are betting on conditional tokens that resolve via Wunderground data, where the frontrunner for 22°C implies the market expects mild winter conditions rather than extreme heat.

Historically, July is São Paulo’s coldest month, with average highs of 21.8°C and daily ranges rarely exceeding 28°C, as confirmed by RipioTurismo and AccuWeather’s July 2026 forecast showing highs between 66°F and 81°F. While Brazil recently experienced a severe heatwave with Rio de Janeiro hitting perceived 62°C, São Paulo’s December record of 35.9°C remains an outlier, and no comparable July extremes have been documented in recent decades, supporting the current 98% probability for 22°C.

Traders should monitor the Brazilian National Meteorology Institute’s (INMET) weekly bulletins for any unexpected cold-front shifts or urban heat anomalies, as these dependencies could alter the 23°C threshold. Although no immediate announcements are scheduled, the settlement window ending 2026-07-09T12:00:00Z requires real-time Wunderground updates, and any deviation from the 21.8°C average would signal a catalyst for the 23°C outcome. Recent DW.com reporting on Brazil’s heatwave underscores the need to watch for regional climate anomalies, even if São Paulo typically remains mild in July.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Kalshi UK, which mirrors the Polymarket order book directly.

Resolution & payout

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

FAQ

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

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.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

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.