Highest temperature in NYC on August 9?

Platform comparison

Market context

The real-world event is the afternoon peak temperature at LaGuardia Airport on 9 August, with the market resolving off Weather Underground’s **Daily Observations** rather than the summary high/low box. Polymarket’s own market page says the contract settles to the range containing the highest recorded LaGuardia temperature for that date, and that later revisions count only until the first observation for the next day is published.[1]

The crowd is currently clustered around **90-91°F**, with a smaller share on **92-93°F**, which is consistent with the published forecast range for New York City around 90°F and with recent station data showing the airport already near the high 80s earlier on 9 August.[1][2][12] That positioning matters because LaGuardia can run a touch differently from citywide forecasts, and the contract is keyed to the station’s final recorded maximum rather than an abstract “New York City” high.[1][6]

For traders, the main catalysts are the day’s actual hourly observations, any late-day warm-up from southerly flow, and the timing of Weather Underground’s next-day rollover, which can lock the result once the first 10 August datapoint appears.[1] On-chain, the price is a direct read on USDC-denominated settlement expectations, so moves often reflect whether the market thinks the final print will land in the 90-91°F band or push into the low 90s; that makes late weather updates, rather than crypto beta, the primary driver here.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically this overview focuses on on-chain pricing: Polymarket's live mid comes from the Polygon conditional-token order book and settles automatically in USDC. The other three venues — Kalshi, Betfair, Manifold — sit alongside as off-chain reference points so you can see how the contract translates across regulatory and settlement regimes.

Resolution & payout

Settlement is on-chain via UMA Optimistic Oracle. A proposer posts the outcome with a bond, a two-hour dispute window opens, then the smart contract lifts winning conditional tokens to 1 USDC and sends payments to holders' wallets automatically. No withdrawal fees beyond Polygon gas.

Off-chain venues (Kalshi, Betfair, Smarkets) settle in local fiat through bank-side clearing — faster than SWIFT, slower than on-chain. Manifold pays no real cash.

UK Frequently Asked Questions

What are crypto prediction markets?

Crypto prediction markets are on-chain smart contracts where you buy YES or NO shares on a future crypto event (e.g. "BTC above $100k by year-end"). The market price between 0¢ and 100¢ is the implied probability.

Why USDC and not ETH or USDT?

USDC is the Polygon standard — audited reserves (Circle, monthly attestation), deepest order book, low gas costs. ETH volatility would distort probability quotes; USDT has thinner Polygon liquidity than USDC.

Is Polymarket legal in the UK?

Polymarket is accessible to UK traders but is not UKGC-licensed. It operates under US CFTC jurisdiction. UK residents face no domestic legal prohibition on using it, but UKGC consumer protections do not apply. For UKGC-regulated alternatives, Betfair Exchange and Smarkets offer similar prediction-style markets.

Do I pay tax on prediction market profits in the UK?

UKGC-licensed platform profits (Betfair, Smarkets) are typically tax-free gambling winnings for UK individuals. Polymarket profits involve USDC crypto transactions, which HMRC treats as Capital Gains Tax events. Keep full transaction records and report via Self Assessment if gains exceed £3,000 per tax year.

How do I deposit on Polymarket from the UK?

UK traders typically fund Polymarket via Coinbase UK, Kraken or Revolut — buying USDC with GBP and transferring to a Polygon-compatible wallet (MetaMask, Coinbase Wallet). Polymarket's onboarding walks you through the bridging process. Typical GBP-to-USDC conversion costs 0.5–1%.