Platform comparison
| Platform | YES odds | NO odds | Fee | KYC | Settlement | |
|---|---|---|---|---|---|---|
Polymarket (via BTC Prediction) Pick polygram.ink (preferred broker) |
100% | 0% | 0% (USDC on-chain) | No-KYC up to $1,500 | USDC, auto via UMA oracle | Open live market → |
Polymarket (direct) polymarket.com |
100% | 0% | 0% | Geo-blocked in US/UK/EU | USDC, on-chain | Open live market → |
Kalshi kalshi.com |
— | — | Up to 7% per trade | US-only, KYC required | USD | Open live market → |
Betfair Exchange betfair.com |
— | — | 2-5% commission | Full KYC from first trade | GBP / EUR | Open live market → |
Manifold Markets manifold.markets |
— | — | Play-money (mana) | None — play-money | Mana (no cash-out) | Open live market → |
Outcome probabilities
Current market-implied probability for each outcome, from the live order book.
| Outcome | Probability |
|---|---|
| 86-87°F | 100% |
| 75°F or below | 0% |
| 76-77°F | 0% |
| 78-79°F | 0% |
| 80-81°F | 0% |
| 82-83°F | 0% |
| 84-85°F | 0% |
| 88-89°F | 0% |
| 90-91°F | 0% |
| 92-93°F | 0% |
| 94°F or higher | 0% |
Market context
LaGuardia Airport's daily high temperature on 13 August 2026 will be recorded and resolved against pre-set Fahrenheit bands. The settlement uses Weather Underground's Daily Observations table as the authoritative source, bypassing summary displays that occasionally diverge from granular station data. USDC settlement occurs post-event confirmation, with resolution tied to the specific instrumental reading at that New York facility rather than broader city estimates or alternative weather stations.
Historical August temperatures at LaGuardia show a median high near 82°F, with extremes ranging from 71°F to 99°F across the past three decades. The 0% crowd probability suggests either extreme confidence in a narrow outcome or sparse early trading volume; August heat in New York typically clusters within a predictable band, making outlier temperatures (below 70°F or above 95°F) less frequently priced in prediction markets. Comparable August days at the airport rarely breach 90°F without specific atmospheric conditions—tropical systems, heat domes, or unusual high-pressure setups that are identifiable weeks in advance.
Traders should monitor National Weather Service forecasts and Atlantic hurricane tracking from mid-July onwards, as tropical remnants occasionally drive anomalous heat or conversely suppress temperatures through cloud cover and precipitation. The settlement window closes at 12:00 UTC on the event date, meaning afternoon readings after market close could shift final outcomes; historical volatility in intraday temperature swings (5–8°F) during summer months warrants attention to forecast updates within 48 hours of the date. Funding rates on related weather derivatives or macro volatility indices may signal institutional positioning ahead of the event.
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 does a transaction cost on Polygon?
- Polygon gas is typically under $0.01 per transaction. A full trade cycle (Approve + Order + Fill) totals around $0.03 — compared to $5-50 on Ethereum mainnet.
- Can I use Bitcoin directly?
- No, Polymarket operates exclusively in USDC on Polygon. You can bridge BTC to USDC via an exchange or bridge service and deposit on Polygon — typically 10-30 minutes processing time.
- 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%.
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