Platform comparison
| Platform | YES odds | NO odds | Fee | KYC | Settlement | |
|---|---|---|---|---|---|---|
Polymarket (via Is Kalshi Legal in California) Pick polygram.ink (preferred broker) |
93% | 7% | 0% (USDC on-chain) | No-KYC up to $1,500 | USDC, auto via UMA oracle | Go to the live market → |
Polymarket (direct) polymarket.com |
93% | 7% | 0% | Geo-blocked in US/UK/EU | USDC, on-chain | Go to the live market → |
Kalshi kalshi.com |
— | — | Up to 7% per trade | US-only, KYC required | USD | Go to the live market → |
Betfair Exchange betfair.com |
— | — | 2-5% commission | Full KYC from first trade | GBP / EUR | Go to the live market → |
Manifold Markets manifold.markets |
— | — | Play-money (mana) | None — play-money | Mana (no cash-out) | Go to the live market → |
Outcome probabilities
Current market-implied probability for each outcome, from the live order book.
| Outcome | Probability |
|---|---|
| 33°C | 93% |
| 34°C | 6% |
| 32°C | 1% |
| 27°C or below | 0% |
| 28°C | 0% |
| 29°C | 0% |
| 30°C | 0% |
| 31°C | 0% |
| 35°C | 0% |
| 36°C | 0% |
| 37°C or higher | 0% |
Market context
Seoul’s late-summer heat is the real-world driver here: the market resolves on the highest *observed* temperature at Incheon International Airport Station during the settlement window, using Weather Underground’s Daily Observations table rather than the summary high/low box. That distinction matters because the station reading can differ from city-wide forecasts, and the event is already priced at 0% YES, so the crowd is effectively dismissing the relevant temperature band despite current August heat in the capital area.[2][4]
The historical frame is that Seoul and nearby stations have already produced extreme readings this week, with Reuters reporting Seoul forecast near 39°C on 6 August and Korean outlets reporting the city topping 40°C on 7 August amid a wider heatwave.[9][10] By comparison, August averages are far lower, typically around 29–31°C for Seoul, which shows how unusual the recent spike is relative to climatology.[6][17] For a temperature-range market, the key reading is not whether it feels hot, but whether the airport station prints into the next band before the day rolls over.[1][2]
Catalysts are mainly operational rather than political: traders should watch the Korea Meteorological Administration short-range forecast for cloud cover, rainfall and wind shifts, plus any airport-area convective showers that could trim the afternoon peak.[4] Reuters has already reported the heatwave’s intensity and official warnings, which supports the case for continued elevated readings, but the settlement source remains the station data on Weather Underground and revisions are only relevant until the first datapoint for the next day is published.[2][9] For accessibility, German GlüStV restrictions can limit participation from Germany-facing users on offshore markets, US CFTC reach can matter for US persons depending on platform structure and market permissions, and “no-KYC up to $1,500” generally means smaller participants can access the market with lighter identity checks until they hit the platform’s verification threshold, which broadens retail participation but does not change the settlement rule.[2]
Methodology
This overview of Highest temperature in Seoul (Incheon) on August 10? reviews the four comparable platforms from a regulatory perspective: which is accessible in your jurisdiction, where KYC kicks in, how the platform is classified by your country of residence. Live probability is the Polymarket mid; comparison columns show regulatory status, KYC thresholds and settlement options for each platform.
Resolution & payout
On Polymarket, resolution runs on-chain via UMA Optimistic Oracle. USDC payout is instant and automatic, with no KYC. Tax treatment depends on your jurisdiction — in the US, gains are usually ordinary income; in the UK, often capital gains. Consult a tax professional for your situation.
FAQ
- Do I need to KYC for Is Kalshi Legal in California?
- Not for lifetime trading volume under $1,500. Above that threshold, a quick KYC flow kicks in — ID, selfie, approximately 5-10 minutes. The threshold matches FATF travel standards for unregulated crypto platforms.
- How are winnings taxed?
- Tax treatment varies by jurisdiction. In most countries, prediction market gains are treated as ordinary income or capital gains. We cannot provide tax advice — consult a tax professional for your specific situation.
- What happens during a tax audit?
- You're responsible for documenting your trades. Is Kalshi Legal in California exports a full transaction history (CSV/PDF) for tax reporting. In an audit you'll need to present these documents.
- Are prediction markets gambling?
- Legally unclear in most jurisdictions. Some interpretations classify them as wagering (gambling regulation applies), others as derivatives (financial regulation applies). There's no global precedent specifically for on-chain prediction markets.
- Is there a withdrawal cap?
- No platform-side cap. You can withdraw any amount provided KYC is complete. SEPA bank withdrawals over €15,000 trigger additional anti-money-laundering checks (statutory obligation for all platforms).
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