Seattle May 17 High Temp: Will It Hit Sixty-Two?

Prediction markets rarely price a two-degree temperature window with this much conviction. The 62-63°F outcome for Seattle’s May 17 high sits at 39.5% probability, with the market leaning toward cooler outcomes by a clear margin. That lean deserves scrutiny. The Pacific Northwest in mid-May is notoriously difficult to call at narrow temperature bands, and the spread of alternative outcomes here tells you the market isn’t sure either.

Seattle’s May climate sits at a hinge point. The region transitions from persistent marine influence to its drier, warmer summer pattern somewhere in late May or early June. On any given day in the second or third week of May, a ridge of high pressure or a persistent onshore flow can swing the afternoon high by six to ten degrees. The market is pricing that uncertainty directly. Here’s what the measurements are telling us: the 62-63°F band is plausible, but so is a run of outcomes in the 58-61°F range that would push resolution away from the primary outcome.

How the Sixty-Two to Sixty-Three Degree Contract Works

This contract resolves YES if Seattle’s official high temperature on May 17, 2026 falls between 62°F and 63°F. It resolves NO if the high lands anywhere outside that two-degree band, including lower outcomes like 60-61°F or 58-59°F, and warmer outcomes like 64°F or higher. Resolution is based on the official recorded high for the day.

• YES (62-63°F): priced at $0.40, implying a 39.5% probability the high lands in this exact band.
• NO (any other outcome): priced at $0.61, implying a 60.5% probability the high falls outside this range in either direction.

The NO outcome here is unusually broad. It wins if Seattle runs warmer than 63°F or cooler than 62°F. Given that mid-May Seattle highs can range from the upper 40s to the low 70s depending on synoptic pattern, a single two-degree band is a narrow target. The market is essentially betting against precision. A strong marine push or a brief ridging event in either direction takes the high outside the window entirely.

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Momentum and Market Signals

The momentum composite across 1-hour and 24-hour intervals shows no directional movement, with a trend score of 55.46. That reading sits just above neutral. No fresh data release or forecast update appears to have moved this contract in the last 24 hours. The market is waiting for the next National Weather Service model run or point forecast update for the Seattle area to provide a sharper signal.

Total market volume stands at $10,000, with $6,828 traded in the last 24 hours. Liquidity is $46,162. Volume below $1 million means this contract is thinly traded. A single large bet or a sharp forecast update could reprice the market quickly. Do not treat the 39.5% probability as a stable consensus. It reflects thin activity, not deep conviction.

Key Factors

• The 1-hour and 24-hour price changes show no movement, suggesting the market has not yet responded to any updated NWS forecast for May 17.
• The trend score of 55.46 reflects mild upward lean but falls well short of a directional signal worth acting on.
• Trader sentiment leans NO at 60.5%, meaning the market views a temperature outside the 62-63°F band as more likely than not.
• Thin volume means liquidity conditions could distort the implied probability if a single participant takes a meaningful position before resolution.
• The spread of alternative outcomes, including 60-61°F, 64°F or higher, and 58-59°F, shows the market distributes probability across multiple adjacent bands, not just above and below the primary outcome.

Lines Analysis: What the Seattle Forecast Data Says

The National Weather Service Seattle forecast office issues point forecasts for Seattle-Tacoma International Airport, the standard measurement location for official high temperature records. The May 17 forecast, as of the most recent model cycle, will be the primary driver of where money flows in this contract before resolution. A forecast high in the 62-64°F range would pressure the YES side. A forecast in the 58-61°F range would reinforce the NO lean already priced in.

What makes NO real is not a single dramatic weather event. It is the ordinary variability of a Pacific marine climate in transition. A low-pressure trough parked off the Washington coast keeps onshore flow active and holds afternoon highs in the upper 50s to low 60s. A temporary ridge builds and lifts the high into the mid to upper 60s. Either pattern takes the high outside the 62-63°F window. The two-degree band is narrow enough that even a forecast centered on 62°F carries meaningful probability of landing at 61°F or 63°F when verified against the actual observation.

Signals to Monitor

• The NWS Seattle Area Forecast Discussion, updated multiple times daily, will flag any change in the synoptic pattern expected for May 17 and signal whether marine influence or inland high pressure dominates.
• The GFS and European ECMWF ensemble model runs for the Pacific Northwest will show the spread of possible high temperature outcomes for May 17, giving a sense of forecast confidence.
• Any shift in the NWS point forecast for Seattle-Tacoma International Airport toward 62°F or 63°F specifically would be bullish for YES and should reprice this thin market.
• A forecast high below 60°F or above 65°F would strongly reinforce the NO side and likely push the YES probability below 30%.
• Overnight temperature trends on May 16 into May 17 will constrain how warm the afternoon can get, making the pre-dawn low a useful early indicator.

The $10,000 in total volume and the 39.5% YES probability reflect a market that has not yet received a definitive weather signal. The data favors a range of outcomes, not a single band. Until the NWS forecast for May 17 tightens to a specific number, the NO side carries the structural advantage simply because it covers more temperature territory.

LINES VERDICT

Leaning No Until the Forecast Confirms the Band

The 62-63°F window is plausible for Seattle on May 17, but a two-degree band in a marine-influenced climate is a narrow target. The data doesn’t care about the politics of a prediction market. It lands where the atmosphere takes it.

What the market says: The 39.5% probability for YES reflects a market that sees this outcome as the most likely single band but still views any other outcome as more probable. Thin volume means this price is fragile. A single updated NWS forecast could move it sharply before the May 17, 2026 resolution.

Key unknown: The National Weather Service Seattle point forecast for May 17. If that forecast lands squarely at 62°F or 63°F with high confidence, YES reprices upward. If it falls below 61°F or above 64°F, NO takes the contract by default.

Frequently Asked Questions

• What does 39.5% probability mean here? The market assigns a 39.5% chance that Seattle’s official high on May 17 falls between 62°F and 63°F. That is the highest probability among all the available temperature bands, but still below 50%.
• What does the NO contract pay out on? NO resolves winning if the Seattle high on May 17 lands at any temperature outside the 62-63°F range, including cooler outcomes like 58-61°F or warmer outcomes like 64°F and above.
• What single event would most move this market? An updated NWS Seattle point forecast placing the May 17 high specifically at 62°F or 63°F would push YES higher. A forecast outside that range in either direction reinforces NO.
• When does this contract resolve? Resolution is set for May 17, 2026, based on the official recorded high temperature for Seattle on that date.
• Is the $10,000 in volume reliable for reading the probability? No. Volume below $1 million means thin liquidity. The 39.5% probability can shift sharply on a single trade or a new forecast update. Treat it as a directional signal, not a settled consensus.

This analysis reflects market conditions as of 2026-05-16 08:20:08. Prediction market probabilities are volatile and shift as new data and regulatory decisions emerge, especially as the 2026-05-17 12:00:00 resolution date approaches. Lines.com does not accept bets or provide financial or gambling advice. All market outcomes are uncertain.