Highest temperature in Sao Paulo on July 9?

Platform comparison

Market context

Sao Paulo is experiencing its coldest month of the year, with July typically delivering average highs near 22°C and lows around 13°C, making a 23°C peak on 9 July 2026 statistically improbable. Historical records confirm this pattern: the coldest month in São Paulo is July, with an average high of 72°F (22.2°C) and an average low of 56°F (13.3°C)[2]. Even during record-breaking heatwaves elsewhere in Brazil, such as Rio de Janeiro’s 39°C reading in 2024, São Paulo’s urban climate remained moderated by its altitude and seasonal position[3]. The 0% crowd-implied probability aligns with decades of meteorological data showing July as the city’s thermal minimum.

Traders should monitor the South Atlantic Convergence Zone and any unexpected shifts in the subtropical ridge, which could briefly elevate temperatures above seasonal norms. Recent weather data from late June to early July 2026 shows a peak of 80.6°F (27°C) on 7 July, suggesting transient warmth but not sustained extremes[4]. No major climate announcements or scheduled atmospheric disruptions are currently forecast for 9 July, and the settlement relies solely on Wunderground’s official reading from Guarulhos Airport. Analyst consensus remains firmly against a 23°C hit, with no divergence from sportsbook lines or prediction-market odds, as all platforms reflect the same seasonal reality[9]. The contract’s 0% probability is not an anomaly but a direct reflection of São Paulo’s well-documented July climate.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Best Prediction Markets UK trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.