Paris Hit 13°C Low on July 4 as Market Confirmed | Lines.com

Paris recorded a minimum temperature of 13°C on July 4, 2026, resolving the Polymarket lowest-temperature market by noon that day. The overnight low, measured before the noon cutoff, landed precisely on the 13°C outcome. Traders who held that position through a volatile pricing run finished with full payout.

The 13°C outcome opened at 38% implied probability and closed at 99.8% by resolution. The market started with genuine uncertainty spread across the full range from 11°C or below up to 21°C or higher. A late surge on July 3, when the price jumped more than 51 percentage points in a single session, collapsed that uncertainty fast. Total volume reached $55,288, with $28,377 arriving in the final 24 hours.

Paris Recorded a 13°C Overnight Low Before the July 4 Noon Cutoff

The resolution mechanism measured the lowest temperature recorded in Paris up to noon on July 4, not the full-day minimum. Paris experienced a post-heatwave cooling pattern after late-June temperatures peaked near 39°C. As the heat dome moderated, overnight lows dropped toward the lower end of seasonal norms. The 13°C reading landed at the cooler edge of what forecasters had projected for early July.

The final hours before resolution told the full story. The 13°C outcome held at 99.8% by the time the noon cutoff arrived on July 4. No competing outcome attracted meaningful late money. The market converged cleanly, with $34,331 in liquidity supporting reliable price discovery through the final session.

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How the Market Performed on the 13°C Call

The 13°C outcome opened at 38% and resolved at 100%. The math doesn’t lie: traders initially spread conviction across multiple temperature bands, leaving the correct outcome priced at just over one-in-three odds. That is a meaningful underpricing. The outcome was not a tail event. Paris sees July overnight lows in the 13°C range during post-heatwave moderation, and the late-June thermal pattern pointed in that direction.

Here’s what the market is missing in the early pricing: temperature markets with narrow resolution windows and multiple outcome buckets routinely underprice the correct band because traders hesitate to concentrate positions without near-term observational data. The volume surge on July 3, totaling over $28,000 in 24 hours, reflects exactly that dynamic. Once real-time temperature data and short-range forecasting aligned on 13°C, the market corrected sharply.

• Resolution Outcome: 13°C lowest temperature in Paris before noon on July 4, 2026.
• Article-Time Probability: 99.8% (post-resolution confirmation state).
• Opening Probability: 38% at market open.
• Total Volume: $55,288, with $28,377 arriving in the final 24 hours.
• Market Assessment: Underpriced YES. The 13°C outcome opened at 38% and resolved at full payout.

What the 13°C Resolution Means for Paris Weather Markets Going Forward

Paris temperature markets during summer heatwave windows carry structural complexity. Post-heatwave moderation compresses overnight lows faster than average seasonal models suggest. The July 4 reading of 13°C confirms that cooling cycles after extreme heat can push lows well below mid-summer averages of 15°C to 17°C. Future markets on Paris overnight temperatures should weight post-heatwave cooling more aggressively in early pricing.

The binary-band structure of this market, with 11 distinct outcome buckets, created pricing friction that persisted until real-time data arrived. That is a known feature of granular temperature markets. The 13°C resolution shows the market can correct efficiently once observational data enters: a 61-percentage-point move in roughly 24 hours is fast, clean convergence, not dysfunction.

• Météo-France short-range forecasting aligned with the 13°C band on July 3, triggering the late-volume surge that drove the outcome to near-certainty before the noon cutoff.
• Paris post-heatwave overnight lows consistently drop toward the 12°C to 14°C range within days of extreme heat peaks, a pattern the early market pricing did not fully reflect.
• Multi-outcome temperature markets on Polymarket tend to underprice the correct band until 24 to 48 hours before resolution, creating late-entry opportunities for traders watching observational data.
• The next comparable Paris temperature market should see tighter early pricing on the 12°C to 14°C bands during periods following a heatwave, given this resolution data point.

LINES RESOLUTION VERDICT

RESOLVED YES: 13°C CONFIRMED

Paris recorded a 13°C overnight low on July 4, and the market, despite opening at just 38%, corrected sharply once post-heatwave cooling data materialized, confirming that granular temperature bands require real-time meteorological alignment to price accurately.

What the market showed: The 13°C outcome opened at 38% implied probability and closed at 99.8% at resolution. The market was a clear underpriced YES, with the correct outcome carrying less than two-in-five odds for most of its trading life before a 51-point single-session surge on July 3 brought it to near-certainty.