Highest temperature in Sao Paulo on June 30?

Platform comparison

Market context

The real-world event centres on the peak temperature recorded at São Paulo–Guarulhos International Airport on 30 June 2026, a date falling within São Paulo’s mildly cool, breezy June season where average highs reach just 23°C[1]. Historical patterns strongly support the crowd-implied 0% probability for extreme heat: June is typically humid but cool, with only 12.5 hours of clear sky and average wind speeds of 18.2 kph[1]. Even recent extremes in June 2026 peaked at only 26°C (78.8°F) on 22 June, far below thresholds that would trigger a “YES” outcome[2]. The 2023 record high of 38.5°C occurred in November, not June, reinforcing that summer heatwaves are seasonally misplaced[5].

Traders should monitor Wunderground’s daily updates for SBGR and any sudden shifts in regional cloud cover or wind patterns, as these directly influence peak temperatures[1]. While no specific weather announcements are imminent for late June, the absence of forecasted heat domes or prolonged clear skies aligns with the 0% implied probability[1]. Analyst consensus across cross-platform odds-comparison tools shows minimal divergence: sportsbook lines for similar June temperature contracts in São Paulo consistently price extreme heat at near-zero, matching prediction-market implied probabilities[2]. This uniformity suggests the market correctly prices the low likelihood of anomalous warmth, with no meaningful catalysts expected to alter the trajectory before the 2026-06-30 settlement window closes.

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

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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'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 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.