Seoul May 16 Low: Will the Thermometer Hit Fifteen?

Seoul’s overnight low on May 16 is now the most actively traded temperature contract on the board. The 15°C outcome just surged to 57% implied probability, picking up more than 26 percentage points in the last 24 hours alone. That kind of move, on a single-day weather contract with less than 36 hours to resolution, tells you traders received new information and repriced fast.

The contract resolves at 2026-05-16 12:00:00. The question is simple: what is the lowest temperature recorded in Seoul on May 16? Traders are currently placing 15°C as the most likely single outcome, with 43% of capital sitting on a different temperature entirely.

How the Seoul May 16 Low Contract Works

This market resolves to the single outcome matching the official lowest temperature recorded in Seoul on May 16, 2026. Resolution is determined by the source designated by Polymarket, which tracks meteorological station data for Seoul. The contract does not pay on a range. It pays only if the recorded low matches the exact outcome you hold.

• 15°C at 0.57: The market assigns a 57% probability that Seoul’s low lands precisely at 15 degrees Celsius on May 16.
• 16°C: The next most likely outcome, reflecting the possibility that the overnight minimum runs slightly warmer than current forecasts suggest.
• 14°C: Covers scenarios where a cooler air mass arrives earlier or more forcefully than models project.
• 13°C or below: Accounts for a more significant cold intrusion, well outside current forecast consensus.
• 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 23°C or higher: These warm outcomes are currently priced at low probability, reflecting late-spring Seoul climatology where overnight lows in the mid-to-upper teens are possible but not favored in current model runs.

The 43% sitting outside 15°C is not noise. Seoul’s overnight low on any given May date can vary by three to four degrees depending on cloud cover, wind direction, and the passage of frontal systems. Missing 15°C by a single degree is entirely realistic. The contract pays nothing for close.

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Momentum and What the Market Is Signaling

The momentum composite here is striking. The 1-hour and 24-hour price changes are identical at plus 26.5%, and the trend score sits at 79.75. That is a single coordinated signal, not a gradual drift. The most likely driver is an updated numerical weather prediction run, specifically from the Korea Meteorological Administration or a global ensemble model, that tightened the forecast range around 15°C as the resolution date approached.

Total volume is $11,726, with $4,627 traded in the last 24 hours. Liquidity sits at $29,462. This is a thin market. Volume under $1 million means a single informed trader or a small cluster of forecast-watchers can move the price sharply. The 26.5% jump reflects exactly that dynamic. Treat the 57% figure as a directional signal, not a stable consensus.

• The 26.5% single-session price surge combined with a 79.75 trend score points to a fresh forecast update driving conviction toward 15°C.
• The 24-hour volume of $4,627 is high relative to total market volume, suggesting new capital entered today rather than existing positions being reshuffled.
• Thin liquidity at this contract size means the price can move another 10 to 15 percentage points on a single late forecast run before resolution.
• The 1-hour and 24-hour change being identical at plus 26.5% indicates the move happened in a compressed window, consistent with a model update or official forecast release rather than gradual sentiment drift.
• Competing outcomes like 14°C and 16°C remain live. A one-degree shift in the forecast consensus would redistribute capital quickly.

Lines Analysis: Seoul Climatology and the Forecast Window

Seoul in mid-May sits in a transitional phase. The Korean Peninsula’s overnight lows during the second week of May historically cluster between 12°C and 18°C, with the distribution peaking around 14°C to 16°C depending on synoptic conditions. A 15°C low is firmly within the climatological core for this date. That is why the market converged here rather than on a warmer or colder outlier.

What makes a non-15°C outcome real is the frontal variability that characterizes spring weather in Northeast Asia. A southerly flow ahead of a passing low-pressure system can push the overnight minimum to 17°C or 18°C. A cold continental airmass trailing a front can drop Seoul to 13°C or 14°C. Neither scenario is climatologically unusual. The question is whether the current synoptic setup favors one of those deviations over the base case.

SIGNALS TO MONITOR:

• Korea Meteorological Administration’s official forecast update for Seoul on May 15 evening: any revision to the overnight low range is the single most important input before resolution.
• Global ensemble model consensus (ECMWF and GFS) for Seoul May 16 low: if spread tightens further around 15°C, current pricing has room to move above 60%.
• Cloud cover and wind direction forecast for Seoul overnight May 15 to 16: clear skies and calm winds favor radiative cooling, pushing the low toward 14°C; overcast conditions and southerly winds favor 16°C or higher.
• Any frontal system timing changes in the Yellow Sea or Korean Peninsula region: a faster or slower front shifts the low by two to three degrees and would reprice all adjacent outcomes.
• Late-breaking observational data from Seoul’s Jongno or Gwanak weather stations as the overnight period begins.

The $11,726 in total volume reflects a market that attracted attention from weather traders who follow short-range meteorological forecasts closely. The data currently favors 15°C, but the gap between 57% and certainty is real. One model run in a different direction before midnight closes the window for repositioning.

LINES VERDICT

Forecast Convergence on Fifteen

The data and the momentum both point to 15°C as the current best estimate for Seoul’s May 16 overnight low, but this is a one-degree precision contract in a transitional weather regime, and the margin for error is exactly the width of a single degree.

What the market says: 57% implies the market is leaning toward 15°C but is far from settled. With thin liquidity and less than 36 hours to resolution, any updated forecast run could reprice this contract by 15 or more percentage points before 2026-05-16 12:00:00.

Key unknown: The Korea Meteorological Administration’s next official low temperature forecast for Seoul on May 16 is the single data point that matters most. A forecast revision of even one degree in either direction would make adjacent outcomes competitive and force a significant repricing.

Scientific Context: Seoul Temperature and Short-Range Forecasting

Short-range temperature forecasting for a major urban station like Seoul is among the most reliable forms of numerical weather prediction. The Korea Meteorological Administration operates a dense observational network across the peninsula, and 24-hour low temperature forecasts for Seoul typically carry an error margin of plus or minus two degrees Celsius. That two-degree uncertainty window spans the gap between 13°C and 17°C, which is precisely where competing outcomes in this market live. The market pricing at 57% for 15°C is consistent with a scenario where the current best forecast centers on 15°C but the uncertainty envelope remains wide enough to keep adjacent outcomes viable. What would move the price meaningfully before 2026-05-16 12:00:00 is a tightening of that forecast envelope in the final operational model runs tonight and early tomorrow morning.

Frequently Asked Questions

• What does 57% probability mean here? The market assigns a 57% chance that Seoul’s recorded low on May 16 lands exactly at 15°C. That leaves a 43% chance spread across all other temperature outcomes.
• What pays out if I hold a non-15°C outcome? Each alternative outcome (14°C, 16°C, 13°C or below, etc.) pays only if the official recorded low matches that exact temperature. No partial credit for being one degree off.
• What single event would move this price most before resolution? An updated official forecast from the Korea Meteorological Administration or a major shift in ensemble model consensus for Seoul’s overnight low on May 16 would reprice this contract immediately.
• When does this market resolve? The contract resolves at 2026-05-16 12:00:00, based on the official lowest temperature recorded in Seoul on May 16, 2026.
• How reliable is the 57% price given low volume? Total volume is $11,726 and 24-hour volume is $4,627. This is a thin market. Low liquidity means the price can shift sharply on a small number of trades, so treat 57% as directional rather than a stable probability estimate.

This analysis reflects market conditions as of 2026-05-15 08:17:00. Prediction market probabilities are volatile and shift as new data and regulatory decisions emerge, especially as the 2026-05-16 12:00:00 resolution date approaches. Lines.com does not accept bets or provide financial or gambling advice. All market outcomes are uncertain.