Highest temperature in Atlanta on July 27?

Platform comparison

Market context

On 27 July 2026, the highest temperature recorded at Hartsfield-Jackson Atlanta International Airport will determine which range wins this market. The settlement window closes at midday UTC, capturing the full diurnal cycle from midnight through the afternoon peak. Current crowd pricing implies 0% probability across all temperature bands, suggesting either a data-loading issue or genuine uncertainty about which range will resolve.

Atlanta's July climatology shows a median high of 89°F, with the 90th percentile reaching 93°F. Historical extremes at KATL include a July record of 100°F set in 2019, though readings above 95°F occur roughly once per decade in midsummer. The city's urban heat island effect and afternoon thunderstorm patterns create volatility; afternoon convection can suppress highs, whilst clear, stagnant conditions drive them upward. Comparable recent July days at the airport have clustered between 88–94°F, with outlier heat events preceded by multi-day high-pressure systems.

The National Weather Service forecast for late July 2026 will be the critical catalyst traders should monitor. Seasonal patterns favour typical summer conditions—warm but not extreme—unless a heat dome establishes itself over the Southeast. Tropical moisture and afternoon thunderstorm activity, common in Georgia's summer, typically cap afternoon highs. Any shift towards a sustained ridge of high pressure or an unusual absence of afternoon convection would push outcomes toward the upper ranges. Traders should watch for NWS outlooks issued 7–10 days prior, which often signal multi-day heat events with reasonable lead time.

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

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 Who Will Win 2026. 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.