Highest temperature in Sao Paulo on July 9?

Platform comparison

Market context

On 9 July 2026, the Sao Paulo-Guarulhos International Airport will record its daily peak temperature, a real-world event that determines whether the prediction market resolves to the 23°C range. The current crowd-implied probability of 0% YES suggests traders believe this specific threshold is virtually unattainable for mid-July in the region, despite recent global heat anomalies.

Historically, July is the coldest month in Sao Paulo, with average highs hovering around 22°C (72°F), making a 23°C reading plausible but not guaranteed [2]. However, recent years have seen significant deviations; July 2023 was the hottest July in 174 years, and extreme heatwaves have pushed temperatures well above averages in neighbouring cities like Rio de Janeiro [1][3]. While the city recorded a record December high of 35.9°C, mid-July typically remains cooler, though the 2026 period has already shown highs reaching 27°C (80.6°F) in late June and early July [4][5]. This divergence between long-term averages and recent volatility frames the 0% probability as potentially too dismissive of emerging climate trends.

Traders should monitor the upcoming weather forecasts for the Guarulhos station, specifically looking for any sudden shifts in cloud cover or wind patterns that could elevate temperatures above the seasonal norm. Recent reports indicate that Brazil is experiencing record-breaking heat, with street thermometers in Sao Paulo hitting 39°C during previous heatwaves, suggesting that extreme conditions are possible even in cooler months [3]. No specific official announcements are scheduled, but the continuous data stream from Wunderground will be the definitive settlement source, requiring traders to watch real-time updates closely as the settlement window approaches [9]. The lack of divergence between sportsbook lines and prediction markets here highlights a consensus that 23°C is unlikely, yet the recent heat data warrants caution against ignoring the possibility of an outlier day [10].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Kalshi vs Polymarket, which mirrors the Polymarket order book directly.

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

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 Kalshi vs Polymarket. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

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 vs Polymarket 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.