Highest temperature in Sao Paulo on July 9?

Platform comparison

Market context

The underlying event is the highest temperature recorded at São Paulo-Guarulhos International Airport on 9 July 2026, measured in degrees Celsius. Polymarket prices this contract today at 0% YES, implying the crowd believes the temperature will not reach the 23°C threshold. This pricing sits on the Polygon network, where USDC funds conditional tokens that resolve automatically once Wunderground publishes the official daily high.

Historically, July is São Paulo’s coldest month, with average highs near 22°C and lows around 13°C[2]. Yet recent climate anomalies have disrupted seasonal norms; July 2023 was the hottest July in 174 years, averaging 16.92°C globally, though local peaks in Brazil have exceeded 35°C in other months[1][5]. The current 0% probability may reflect seasonal expectations, but it ignores the volatility introduced by record-breaking heatwaves that have scorched Rio and São Paulo in recent years, with heat indices hitting 62.3°C[3].

Traders should monitor the Brazilian National Meteorology Institute’s (INMET) weekly forecasts and any sudden shifts in the South Atlantic high-pressure system, which often dictates winter temperatures. A recent Al Jazeera report highlighted how rapid heat spikes can occur even in traditionally cool months, suggesting that a single anomalous day could invalidate the crowd’s certainty[3]. Additionally, watch for updates from Wunderground’s SBGR station page, as data gaps or sensor recalibrations could delay resolution or alter the recorded high[9]. The on-chain mechanics will resolve only if the official reading matches exactly 23°C, making precision critical.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Sao Paulo on July 9? 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 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.