Los Angeles weather on May 18, 2026 will provide a definitive resolution: the National Weather Service will record the high temperature at one of the city's official stations. This market focuses on an unusually narrow range—just a single degree between 62°F and 63°F—making it one of the most precise temperature predictions available on any prediction market. At 1% YES odds, the market is pricing in near-zero probability of this exact outcome occurring. Current seasonal patterns suggest mid-May highs in Los Angeles typically cluster in the upper 70s to low 80s, making a 62-63°F high an extreme outlier scenario requiring significant weather disruption from typical May conditions. The low odds reflect both the statistical rarity of such a cool day and the inherent difficulty of pinpointing weather within a one-degree band with precision. The 99% NO odds underscore trader confidence that May 18 will see substantially warmer conditions than this narrow range implies. Such tight temperature bands attract precision-focused traders seeking to exploit gaps between professional weather forecasts and market pricing.
What factors could move this market?
Los Angeles's climate in mid-May typically shows stable warming patterns, with high temperatures between 75°F and 82°F on average during this period. A high of 62-63°F would represent a significant departure from seasonal norms, roughly 15-20 degrees cooler than recent May historical averages. Such an outcome would require specific atmospheric conditions: either a Pacific coastal low-pressure system bringing onshore flow and marine layer cloud cover, or an unusually persistent trough of low pressure aloft. Historical parallels suggest this is not impossible—LA experiences occasional cool May days driven by early June precipitation systems that occasionally reach the region in late May—but such events occur in perhaps 2-3% of May days in any given year.
What could push the market toward YES? A strong Pacific low-pressure system developing off the California coast, combined with persistent marine layer stratus clouds over the LA basin, would suppress daytime heating. Cold-air advection aloft, typical of coastal upwelling events, could also contribute. Secondary factors include seasonal precipitation arriving early, which would both lower temperatures directly and increase cloud cover. Such scenarios are monitored by meteorologists and reflected in ensemble forecasts several days in advance.
What argues for NO? The current date (May 17) offers very short lead time for such forecasts. Most weather models at this range show typical late-May warming for Southern California. Persistent high-pressure patterns remain more common than troughs. Marine layer influence is often limited in duration, typically burning off by mid-to-late morning in May. The 1% price suggests the market sees this as a tail-risk event, one that would require confluence of multiple rare conditions simultaneously.
The 99% NO odds reflect rational pricing given both climatological precedent and the precision requirement. Even if May 18 turns out genuinely cool—say, a 68-70°F high—the market still resolves to NO. The one-degree bandwidth is the critical constraint. This makes the contract valuable primarily to meteorological edge-case traders with confidence in specific numerical ranges. The $9,076 liquidity is modest for such a precise outcome, suggesting limited mainstream participation. Most prediction market participants avoid such tight temperature bands due to both low probability and difficulty in forecasting with that precision. The 24-hour volume of $2,630 shows thin trading activity, consistent with a niche market. These dynamics leave space for specialized traders with superior weather models and conviction in their forecasts.
What are traders watching for?
National Weather Service releases official LA high temperature at midnight UTC May 18; resolution occurs immediately upon data availability.
Marine layer persistence through mid-day; if burned off early, conditions favor warmer temperatures inconsistent with 62-63°F range.
Pacific high-pressure system tracking: forecast models show ridge strength determining whether cool trough influence reaches Southern California.
Cloud cover development: satellite loops on May 17-18 reveal stratus extent; persistent overcast favors lower highs.
How does this market resolve?
Market resolves May 18 based on NWS official LA high temperature: YES if 62-63°F, NO otherwise. Resolution data typically available within 24 hours of the observation day.
Polymarket Trade is an independent third-party interface to the Polymarket CLOB prediction market exchange on Polygon — not affiliated with Polymarket, Inc. Prediction markets aggregate trader expectations into real-time probability estimates. 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. Polymarket Trade is non-custodial — your funds never leave your wallet. Open the full interactive page linked above to place orders, see order book depth, and execute a trade.
