Pronóstico: Highest temperature in Sao Paulo on June 30?

Platform comparison

Market context

The highest temperature recorded on 30 June 2026 at São Paulo–Guarulhos International Airport is the real-world event this market resolves to, with the crowd currently implying a 0% probability that it will fall into the specified range. Polymarket prices this contract today as a near-certain NO, reflecting the on-chain mechanics where USDC on the Polygon network is used to back conditional tokens that expire when the settlement window closes at 12:00 UTC on 30 June 2026. Traders holding long positions on the YES side are effectively betting against the overwhelming market consensus, which treats the event as statistically improbable given current data.

Historical patterns for São Paulo in June show the city experiences mildly cool, breezy conditions with average highs of 23°C (73°F) and lows of 13°C (55°F), while humidity remains high at 82% [1]. Recent data from June 2026 confirms this trend, with the highest temperature recorded so far in the month being 26.0°C (78.8°F) on 22 June, and the lowest dipping to 9.4°C (48.9°F) on 18 June [2]. Even the city’s hottest day in recent history occurred in November 2023 at 38.5°C, far outside the typical June range, suggesting that a June 30 spike into the target range is inconsistent with established climatic behaviour [5].

Traders should monitor the official Wunderground daily report for São Paulo–Guarulhos, which serves as the definitive resolution source, and watch for any unexpected weather anomalies or extreme heat announcements from local meteorological services. While no specific forecast predicts a temperature spike for 30 June, the dependency on real-time data means that any sudden deviation from the seasonal average would be the primary catalyst for a shift in probability [4]. The market’s current 0% pricing assumes continuity with the mild June pattern, so any catalyst breaking this trend—such as an unforecasted heatwave—would be the only factor capable of altering the outcome, though such events remain rare in this season.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Pronóstico: 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

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

Where can I trade this market with the lowest fees?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Polymarket Qué Es. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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 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.