Highest temperature in Sao Paulo on June 30?

Platform comparison

Market context

On 30 June 2026, the highest temperature recorded at São Paulo–Guarulhos International Airport will determine the outcome of a weather-based prediction market, with the settlement window closing at 12:00 UTC. The current crowd-implied probability of 0% for a "YES" outcome suggests traders expect the temperature to fall outside the defined range, likely due to historical patterns in June. Recent data shows the peak temperature in São Paulo during mid-June 2026 was 78.8°F (26.0°C) on 22 June [2], while July is typically the coldest month, averaging highs of 72°F (22.2°C) [3]. Historical extremes for June remain moderate, with no recorded days exceeding 30°C in recent decades, reinforcing the low probability of a high-temperature event.

Traders approaching this market programmatically should monitor real-time weather feeds from Wunderground, the designated resolution source, and cross-reference with PredictWind’s historical June datasets for São Paulo [7]. Key catalysts include any sudden shifts in regional cloud cover, wind patterns, or unseasonal heatwaves, which could be influenced by broader climate anomalies. Although no specific weather announcements are imminent, traders should watch for updates from Brazil’s National Meteorological Institute (INMET) regarding June temperature forecasts. Recent climate reports note that São Paulo has experienced record December highs of 35.9°C, but June remains consistently mild [4]. A conditional order strategy could be deployed to adjust positions if Wunderground data shows temperatures approaching 28°C before settlement.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Sao Paulo on June 30? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

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.

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.

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.