San Francisco July 4 High Temp: 70-71°F Leads at 35%

San Francisco’s Fourth of July weather is notoriously hard to pin down. The city’s microclimate sits at the intersection of marine layer influence, bay wind patterns, and inland heat draw. The 70-71°F range currently holds 35% implied probability on this market, but a sharp 5.5% price drop in the last hour signals that traders are reassessing. The market is pricing uncertainty, not science.

The market question asks: what will the highest temperature in San Francisco be on July 4, 2026? The 70-71°F outcome is priced at $0.35 YES and $0.65 NO. The contract resolves on July 4, 2026. Total volume stands at $9,710, with all of that arriving in the last 24 hours.

How the San Francisco Temperature Contract Works

This market resolves based on the single highest temperature recorded in San Francisco on July 4, 2026. One outcome wins. The 70-71°F bracket captures a historically common range for the city on Independence Day, but ten other brackets compete for probability. Resolution is determined by the official measurement source cited in the market terms.

• 70-71°F (YES, $0.35): The market’s current favorite at 35% probability, reflecting historical frequency and current forecast alignment.
• 68-69°F (competing bracket): The cooler adjacent range, which gains if marine layer strengthens or fog holds longer than expected.
• 72-73°F (competing bracket): Captures a warmer outcome if inland pressure systems pull the fog back before afternoon peak.
• 74-75°F and 76°F or higher (competing brackets): Lower probability but real if a heat event pushes through the Bay Area on the holiday.
• 66-67°F and below (competing brackets): Fog-locked scenarios where marine influence dominates through midday.

Missing the 70-71°F bracket doesn’t require a dramatic weather event. A fog bank that holds until 2 p.m. pushes the high into the 66-69°F range. A light offshore flow in the morning shifts the high toward 72-75°F. San Francisco temperatures can diverge by 6-8°F from one part of the city to another, making the measurement station location a real factor in resolution. The market accounts for that uncertainty in its spread across competing brackets.

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Momentum and Market Signals

The 1-hour momentum composite tells a clear story: this market moved sharply bearish on the 70-71°F outcome in the last hour. The trend score of 49.96 sits just below neutral, reflecting genuine two-sided uncertainty rather than consensus. The likely driver is updated National Weather Service forecast data for the July 4 period, which may be shifting the probability mass toward adjacent temperature brackets.

Total volume is $9,710, with all of it arriving in the last 24 hours. Liquidity sits at $42,062, which is healthy relative to volume. Because total volume is well below $1 million, a single large trade can move this price sharply. Thin volume markets like this one reprice fast when new forecast data drops.

• 1-hour change of -5.5% on the 70-71°F outcome suggests forecast data or trader reallocation is pulling probability toward cooler or warmer adjacent brackets.
• All $9,710 in volume arrived in the last 24 hours, meaning this market just activated. Early positioning often overshoots before settling.
• Liquidity of $42,062 is more than four times total volume, which means the order book can absorb repositioning without extreme price impact.
• Trend score of 49.96 confirms no directional conviction. The market is genuinely split on which adjacent bracket captures the high.
• Trader sentiment leans 35% YES / 65% NO on the primary outcome, consistent with a multi-bracket market where the leader holds a plurality, not a majority.

Lines Analysis: San Francisco Marine Layer vs. Inland Heat

Here’s what the measurements are telling us. San Francisco’s July 4 high temperature historically clusters between 64°F and 74°F, with the 68-72°F range appearing most frequently. The 70-71°F bracket is a reasonable plurality leader in any flat-prior model of this market. National Weather Service forecasts for early July 2026 show the Bay Area under typical summer pattern: morning marine layer, afternoon clearing, peak temperatures in the early-to-mid afternoon before sea breeze reinforces.

The case against 70-71°F is straightforward. If an upper-level ridge strengthens over California through July 3-4, afternoon highs in San Francisco proper can push into the 74-78°F range. Conversely, a deepening marine layer, which is not unusual during holiday weekends when inland demand for cool air is lower, can suppress the high to 64-68°F. The data doesn’t care about the politics of a July 4 forecast. Marine layer and inland pressure determine the outcome, not expectations.

• National Weather Service Bay Area forecast updates between now and July 4 morning will be the primary price mover for all brackets in this market.
• Morning fog burn-off timing is the key variable. Fog clearing before noon favors 70-73°F. Fog holding past 1 p.m. favors 64-68°F.
• Inland California heat forecast matters because strong inland heat draws marine air inland, paradoxically suppressing San Francisco highs while warming interior valleys.
• Measurement station specifics will determine resolution. Downtown and airport stations can read 4-6°F apart on the same afternoon.
• Adjacent bracket repricing in the 68-69°F and 72-73°F outcomes will signal where market consensus is migrating before resolution.

Total volume of $9,710 reflects a market that just opened for active trading. The 70-71°F outcome holds the plurality at 35%, but six competing brackets each hold meaningful probability. The data currently favors the 70-71°F range as the single most likely outcome, but the market is correct to price it well below 50%. A multi-bracket weather market with this many competing outcomes will rarely see any single bracket exceed 40-45% even with strong forecast alignment.

LINES VERDICT

PLURALITY LEADER, NOT FAVORITE

The 70-71°F bracket leads on historical frequency and current forecast alignment, but a ten-bracket market means 35% probability is the ceiling for any single outcome without an unusually strong meteorological signal.

What the market says: 35% implied probability on 70-71°F reflects genuine multi-outcome uncertainty. Volume below $1 million means this price will move sharply if the July 4 morning forecast sharpens in either direction before noon resolution.

Key unknown: The National Weather Service Bay Area forecast update on July 4 morning, specifically fog burn-off timing, is the single data point that will reprice every bracket in this market before resolution.