Highest temperature in Sao Paulo on June 30?

Platform comparison

Market context

The 0% crowd-implied probability for a high temperature exceeding the upper range on 30 June 2026 at São Paulo-Guarulhos reflects a stark reality: June is the coolest month in São Paulo, with historical highs averaging just 23°C and rarely breaching 26°C. Recent data confirms this pattern, showing the highest maximum temperature for the entire month of June 2026 was only 26.3°C on 29 June, while the lowest minimum plummeted to a record 9.3°C on 18 June[4]. This aligns with long-term averages where daily highs hover around 72°F (22°C), rarely exceeding 79°F (26°C), making any extreme heat event statistically improbable for this specific date[2].

Traders should monitor the departure from the monthly mean temperature, which this year sits at -1.2°C below normal, indicating a persistent cool anomaly rather than a warming trend[4]. While a severe heat wave recently gripped Rio de Janeiro with perceived temperatures reaching 62°C, meteorological services forecast rain and easing temperatures for the coming days, suggesting such extremes are unlikely to migrate to São Paulo in the southern hemisphere winter[5]. The key dependency is the forecast for the final days of June; given the current cool baseline and the typical three rainy days in the month, the catalyst for a breach would require an unprecedented, unforecasted atmospheric shift, which current models do not support[3].

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.

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 Prediction Today 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.