Highest temperature in London on July 4?

Platform comparison

Market context

The market resolves on the highest temperature recorded at London City Airport on 4 July 2026, with the current crowd-implied probability for a "YES" outcome sitting at 0%. Historical data frames this near-zero stance as a reaction to modest insolation and light winds, which typically push peak readings toward the seasonal July average of 22–23°C rather than the extreme highs required for a positive resolution. While London recorded a provisional 40.2°C at Heathrow in July 2022, such anomalies are rare and usually driven by intense, sustained heatwaves that the current atmospheric conditions do not yet support[7]. The frontrunner outcome remains 28°C at 41%, suggesting the book is pricing in a modest deviation from the mean rather than a catastrophic spike[1].

Traders should monitor the Met Office daily highest gust forecasts and the specific insolation schedules for the coming days, as these dependencies directly dictate whether temperatures breach the 28°C threshold. Recent analysis notes that thin volume and a two-day window to resolution have created volatility, with the 28°C price dropping 12% amid shifting sentiment[8]. Crucially, the market's traction is tied to the funding flows that drive its book depth; as deposit fees and withdrawal rails like Klarna and SEPA become more efficient, capital inflows will likely stabilise these volatile prices. The settlement window ending 12:00 UTC on 4 July 2026 means any late-morning heat surge could instantly invalidate the current 0% probability, making the timing of these weather announcements a critical catalyst for immediate price action[5].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares Highest temperature in London on July 4? with a focus on payment rails and deposit friction. Polymarket accepts USDC on Polygon only; Kalshi only ACH/Plaid (US only); Betfair card/SEPA in EU/UK; Manifold no deposit. Polymarket Klarna UK additionally offers Klarna and SOFORT as fiat on-ramps to USDC. Live odds reflect the Polymarket order book.

Resolution & payout

Settlement path determines payout latency. Polymarket settles on-chain (USDC, minutes). Broker frontends like Polymarket Klarna UK add Klarna/SOFORT as fiat withdrawal options with T+1 processing. Kalshi: USD via ACH (T+1 to T+3). Betfair: local currency via card/SEPA (T+1 to T+5).

FAQ

What does SOFORT cost as a deposit method?

Polymarket Klarna UK charges no fees for SOFORT. The only cost is the internal FX spread (typically <1%) on EUR→USDC conversion. SOFORT itself has no end-user fees — the platform absorbs acquirer costs.

How fast is SEPA deposit?

SEPA Instant: under 10 seconds. SEPA Standard: 1-2 business days. Both accepted fee-free; the internal USDC conversion runs automatically once EUR lands in the platform account.

Can I deposit with a credit card?

Yes, Visa and Mastercard. Credit card deposits carry a ~2.5% acquirer surcharge (standard for card payments). Apple Pay and Google Pay run on the same card rails — same surcharge.

How do withdrawals work?

Identical methods in reverse. SEPA withdrawal: T+1 (standard) or under 10 seconds (SEPA Instant). Klarna withdrawals process via bank-account refund. USDC withdrawal to external wallet: Polygon gas cost (typically $0.01).

Are payment details protected?

Yes. Card and bank details are never stored by Polymarket Klarna UK — they pass directly through PCI-DSS compliant payment service providers (Adyen, Stripe). Polymarket Klarna UK retains only transaction IDs and Klarna reference numbers for reconciliation.