This prediction market tracks whether San Francisco's high temperature on April 28 will fall within the unusually narrow 52-53°F range. At 0% YES odds, traders express near-certainty that the actual high will deviate from this band. Late April in San Francisco typically sees highs between 62-68°F as spring weather strengthens. A high of 52-53°F would represent a significant cooling event, roughly 10-15 degrees below seasonal norms. Such conditions would require an unusual pattern—perhaps an unexpected marine layer surge, persistent high cloud cover, or an early-season cold push from the north. The extreme rarity of such conditions explains the market's pricing. The narrow 1-degree specification itself makes this a highly targeted forecast compared to broader temperature range markets, where picking any specific 1-degree band has inherently low probability.
Deep dive — what moves this market
San Francisco's marine microclimate creates a unique weather regime where spring temperatures are moderated by Pacific Ocean influence and frequent coastal fog. April is typically a transition month—early April sees highs around 60-62°F while late April edges toward 66-68°F as solar angles increase and day length reaches 14+ hours. A high of 52-53°F would be nearly 15 degrees below April's typical range and comparable to late February or early March conditions. Such a cool day would require specific atmospheric blocking: either an unusually persistent marine layer from a marine high-pressure system, a cold-air advection event from inland valleys, or unexpected upper-level support for cloud cover. Historically, San Francisco rarely experiences April highs below 54°F unless a rare atmospheric event occurs—perhaps a departing cold front with slower-than-normal marine boundary layer recovery, or a westward-tracking upper-low bringing anomalous northwesterly flow. The current 0% market price reflects trader consensus that the probability of hitting this exact 52-53°F window on April 28 specifically is effectively zero. The market treats this as a tail-risk scenario: even if San Francisco experiences an unusually cool day (say, a high of 55-57°F), that would still resolve the market to NO because it falls outside the specified range. This highlights how prediction markets can price extremely specific forecasts—the difference between "cool day" and "extremely cool day in a narrow band" is substantial in probabilistic terms. The market appears to view even a 20-30% chance of hitting 52-53°F as unrealistic given no major weather warnings exist for April 28. The wide bid-ask spread on this market likely reflects the fundamental difficulty in pricing extremely specific temperature windows where traders see almost no realistic path to YES resolution.
What traders watch for
NOAA National Weather Service final forecast for San Francisco on morning of April 28
Persistence and intensity of marine layer and low-level cloud cover through the day
Upper-level atmospheric patterns and any cold-air advection from inland regions
Official high temperature report must fall within exactly 52.0–53.0°F to resolve YES
Historical precedent check: whether San Francisco has ever recorded April 28 highs below 54°F
How does this market resolve?
Market resolves YES if NOAA's reported high temperature for San Francisco on April 28, 2026 is between 52.0°F and 53.0°F (inclusive). Any high outside this range resolves the market NO.
Prediction markets aggregate trader expectations into real-time probability estimates. On Polymarket Trade, every market question resolves YES or NO based on a specific event outcome; traders buy shares of the side they believe will resolve positively. Prices range 0¢ (certain no) to 100¢ (certain yes) and naturally reflect the crowd-implied probability of YES. This page summarizes the market state for readers arriving from search; for live trading (place orders, see order book depth, execute a trade) open the full interactive page linked above.
