Highest temperature in Sao Paulo on July 6?

Platform comparison

Market context

The underlying real-world event is whether the highest temperature recorded at São Paulo-Guarulhos International Airport on 6 July 2026 will reach the threshold set for a “YES” outcome in this prediction market. Today, Polymarket prices this contract at 0% YES, implying the crowd believes the temperature will fall well below the required level. This stark pricing reflects São Paulo’s typical July climate, where average highs hover around 22°C (72°F), with July being the coldest month of the year in the region[3]. Historical data shows São Paulo’s hottest day reached 37.7°C only on 24 September 2023, while its coldest was 3.7°C on 30 July 2021[8]. Even Brazil’s national record of 44.8°C occurred during an extreme heatwave in a different region, not in São Paulo’s urban core[1]. These comparable cases suggest the 0% probability is grounded in solid climatic precedent.

Traders should monitor any sudden shifts in regional weather forecasts, particularly announcements from Brazil’s National Meteorology Institute (INMET) regarding heatwave developments or cold front movements. While no major heat event is currently forecast for São Paulo in early July 2026, unexpected atmospheric anomalies could alter temperatures. PredictWind’s historical weather records for São Paulo in July 2026 indicate stable, moderate conditions with no extreme spikes expected[2]. Additionally, traders must watch for updates on Wunderground’s data feed, which serves as the official resolution source for this market. Any delays or discrepancies in temperature reporting could impact settlement timing. Though no recent news source explicitly forecasts a heat spike for São Paulo this week, the broader context of Brazil’s recent temperature records—such as July 2023 being the hottest in 174 years—warrants caution[6]. The on-chain mechanics, including USDC settlement on Polygon and conditional token execution, ensure transparent, automated resolution once Wunderground confirms the day’s peak temperature.

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

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

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 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 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?

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

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.