Miami Low Temp May 31: Can 78-79°F Hold?

Miami’s overnight low on May 31 is sitting at the center of a genuinely competitive prediction market. The 78-79°F bracket holds a 48% implied probability, barely ahead of the field, with a 25% price surge in the last 24 hours pointing toward fresh conviction. That momentum is meaningful. It signals traders are actively repositioning ahead of the noon resolution window.

The market question asks: what is the lowest temperature recorded in Miami on May 31? The primary outcome, 78-79°F, is priced at $0.48 YES and $0.52 NO. The market resolves at noon Eastern on May 31, 2026, with $6,635 in total volume and $4,578 traded in the last 24 hours.

How the 78-79°F Contract Works

A YES resolution requires Miami’s official low temperature reading on May 31 to land between 78°F and 79°F, inclusive. A NO resolution means the low falls into any other bracket: cooler toward the 74-75°F or 76-77°F ranges, or warmer toward 80-81°F and above. The National Weather Service Miami office provides the official temperature record used for resolution.

• 78-79°F (primary): $0.48 YES, $0.52 NO, 48% implied probability
• 80-81°F: competing bracket, warmer scenario
• 76-77°F: competing bracket, cooler scenario
• 74-75°F and below: lower-probability cool outcomes
• 82-83°F and above: lower-probability heat outcomes

The NO side covers a wide range of outcomes. Miami’s overnight low missing the 78-79°F window happens when either a stronger-than-expected onshore flow pushes the low into 80°F or above, or a passing dry air mass briefly drops readings into the upper 70s or below. Late May in Miami typically sees overnight lows clustering in the 76-80°F range, which means multiple adjacent brackets compete directly with the primary outcome.

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Momentum and Market Signals Heading Into Resolution

The combined momentum signal here is bullish for the 78-79°F bracket. A flat 1-hour change paired with a 25% 24-hour surge and a trend score above 65 suggests a decisive repricing event happened earlier on May 31, not gradual drift. The most likely driver is an early morning temperature reading consistent with the 78-79°F range, prompting traders to front-run the noon resolution.

Total volume sits at $6,635, with $4,578 of that trading in the last 24 hours. That 24-hour concentration is notable: nearly 70% of all volume arrived in a single day. Liquidity is deep at $49,882, which means a large single trade would not dramatically move the price. But with total volume well under $1 million, this market is thin enough that a few motivated traders drove the 24-hour spike.

• The 24-hour price jump of 25% is the strongest directional signal in this market, likely tied to early May 31 temperature observations.
• The 1-hour flat reading suggests the repricing has stabilized, not accelerated further.
• Liquidity at $49,882 far exceeds volume at $6,635, meaning the order book is not being exhausted by trading activity.
• Thin total volume means the 48% implied probability reflects a small number of active participants, not broad market consensus.
• The trend score of 65.13 places this market in moderate conviction territory for the 78-79°F outcome.

Lines Analysis: Miami’s Late-May Temperature Profile

Late May in Miami sits in a transitional window. The city has typically left its dry season behind, with rising humidity and warm Atlantic sea surface temperatures keeping overnight lows elevated. The 78-79°F bracket aligns with historical late-May overnight lows in Miami, which regularly cluster in the upper 70s. The National Weather Service Miami forecast for late May 2026 has consistently pointed toward warm, humid nights with little frontal activity to drag lows below the mid-70s range.

What makes the NO side real is bracket competition, not outlier weather. The 80-81°F bracket is the most direct threat: if overnight humidity is higher than average and winds remain southerly off the warm Atlantic, the low could hold above 80°F. The 76-77°F bracket becomes relevant if any dry air intrusion or brief clearing cuts the overnight low by a degree or two below the primary bracket floor. Neither scenario requires unusual meteorology. They just require the low to land one or two degrees away from the 78-79°F window.

• National Weather Service Miami: any post-midnight temperature observation near or above 80°F would reprice the 80-81°F bracket sharply upward before resolution.
• Atlantic sea surface temperatures: anomalously warm nearshore waters raise overnight minimums, pushing the low toward 80°F and above.
• Wind direction at Miami International Airport: southerly flow favors warmer minimums; any north or northeast component could nudge the low into the 76-77°F bracket.
• Official hourly surface observation (METAR): the pre-noon reading closest to dawn typically captures the daily low and will drive final resolution.

The data at $6,635 in total volume reflects a small, active trader pool making calibrated bets on a narrow temperature window. The 24-hour price surge suggests participants have early observational data. The 78-79°F bracket holds the highest single probability at 48%, but it does not hold a majority. The competing brackets collectively price a 52% chance the low lands elsewhere.

LINES VERDICT

Contested Favorite

The 78-79°F bracket is the single most likely outcome, but the market has not reached conviction. The 24-hour repricing surge suggests observational data supports this range, yet the competing brackets retain majority collective probability.

What the market says: A 48% implied probability means traders see the 78-79°F bracket as the best single bet, but the market is pricing real uncertainty across adjacent ranges. With resolution arriving at noon Eastern on May 31, any final pre-dawn temperature observation is the live catalyst.

Key unknown: The official National Weather Service surface observation at Miami International Airport in the hours immediately before noon resolution is the single data point that determines this market. A reading at or above 80°F or at or below 77°F would invalidate the primary bracket entirely.

Scientific Context: Miami’s Late-May Temperature Baseline

Miami’s late-May climate sits firmly in pre-hurricane season conditions. Sea surface temperatures in the Florida Straits and Biscayne Bay typically run 83-85°F by late May, suppressing overnight cooling and keeping low temperatures elevated. The urban heat island effect at Miami International Airport, the official observing site, adds another one to two degrees to overnight minimums compared to surrounding suburban areas. These structural factors make sub-76°F overnight lows genuinely rare in late May. The 78-79°F bracket sits at the statistical core of what Miami typically records at this time of year.

How does 48% probability work here?

A 48% implied probability means the market assigns roughly a one-in-two chance the overnight low lands between 78°F and 79°F. It is the leading single outcome but not a majority prediction.

What pays out on a NO resolution?

A NO resolution on the 78-79°F contract means the Miami daily low recorded any temperature outside that two-degree window. Traders holding NO contracts profit if the low lands in any adjacent or distant bracket.

What data event could reprice this market before resolution?

An official hourly surface weather observation from Miami International Airport showing a temperature at or above 80°F or at or below 77°F between midnight and noon Eastern would immediately shift probability away from the 78-79°F bracket.

When does this market resolve?

The market resolves at noon Eastern on May 31, 2026. The resolution window is tight, making any pre-dawn or early morning temperature observation the decisive data point.

Is the volume reliable enough to trust the price?

Total volume is $6,635, well below $1 million. Thin volume means a small number of traders are driving the 48% price. The signal carries weight but reflects limited participation, not broad consensus.