New Orleans Temperature Market Guide

Louis Armstrong New Orleans International Airport (KMSY) serves as the official temperature recording station for New Orleans weather markets. Located in Kenner, Louisiana, approximately 11 miles west of downtown New Orleans, the station sits at just 4 feet above sea level in the flat Mississippi River delta region.

The station's proximity to Lake Pontchartrain to the north and the Gulf of Mexico to the south creates a unique microclimate. The flat terrain and abundant water bodies mean temperatures are heavily influenced by wind direction and moisture content rather than elevation or terrain effects.

KMSY uses standard ASOS equipment with temperature reported in whole degrees Fahrenheit after conversion from Celsius readings, following the standard rounding protocol where 0.5°C rounds to the nearest whole number.

New Orleans experiences a humid subtropical climate (Koppen: Cfa) characterized by hot, humid summers and mild winters. The city's position on the Gulf Coast ensures abundant moisture year-round, with humidity regularly exceeding 90% during morning hours.

Summer temperatures typically reach the low-to-mid 90s°F, but readings above 95°F are relatively uncommon due to the moderating influence of afternoon sea breezes and frequent convective storms. The Gulf of Mexico acts as a temperature buffer, preventing the extreme heat seen in inland locations.

Winters are mild with highs typically in the 60s°F, though cold fronts can occasionally push temperatures into the 40s or even 30s. Hard freezes are rare but can occur when Arctic air penetrates deep into the Gulf region.

Winter (December - February): Mild conditions with highs in the 60s°F. Cold fronts create periodic temperature swings of 20-30°F. Watch for post-frontal clearing that can lead to surprisingly cool readings.

Spring (March - May): Warming trend with increasing humidity. Temperatures climb from the 70s into the 80s. Strong frontal passages become less frequent. Sea breeze patterns begin to establish.

Summer (June - August): Hot and humid with highs in the low 90s°F. Afternoon thunderstorms are nearly daily occurrences. The sea breeze provides reliable afternoon cooling. Tropical systems can significantly impact temperatures.

Fall (September - November): Gradual cooling with decreasing humidity. Hurricane season peaks in September. Temperatures fall from the 80s back to the 70s and 60s. First cold fronts arrive in October.

The Gulf of Mexico influence is the dominant factor in New Orleans temperature forecasting. Wind direction is critical - southerly flow off the Gulf keeps temperatures moderate and humid, while northerly flow behind cold fronts brings drier, more variable conditions.

Afternoon thunderstorms in summer can drop temperatures 10-15°F within an hour. Check radar and convective forecasts, especially for the 2-6 PM window. If storms develop over or near the airport, the afternoon high may occur in the morning hours instead.

Humidity affects perceived temperature accuracy. High dewpoints can suppress daytime heating slightly, as energy goes into evaporation rather than temperature increase. Summer highs rarely exceed 96°F despite the latitude.

Morning fog is common, especially in fall and winter. Dense fog events can delay temperature rise significantly, impacting when the daily high occurs. Monitor visibility forecasts for morning trading decisions.

For tropical systems, track the storm position relative to KMSY carefully. Storms passing to the west typically bring warmer, southerly flow. Storms passing to the east bring cooler, northerly flow and rain-cooled air.

New Orleans temperature markets resolve using the official daily high temperature recorded at KMSY as published in the NWS CLI (Climatological Data) report. The CLI report is issued by the NWS New Orleans (LIX) forecast office.

The daily maximum temperature observation runs from midnight to midnight local time (Central Time). This means the "high temperature" for a given calendar day reflects the warmest reading between 12:00 AM and 11:59 PM CT.

View the latest KMSY CLI Report →

Sea Breeze Timing: The onset and strength of the Gulf sea breeze significantly impacts afternoon temperatures. Early development can cap highs in the upper 80s; delayed development allows low-to-mid 90s.

Convective Activity: Daily thunderstorms in summer create high uncertainty. Storm timing, location, and coverage determine whether the high occurs before or after convection develops.

Tropical Influences: From June through November, tropical systems can dramatically alter the temperature regime. Even distant storms affect moisture, cloud cover, and wind patterns.

Lake Pontchartrain Effects: The large lake to the north of the city creates its own local breeze patterns that can interact with or oppose the Gulf sea breeze.

Urban Heat Island: KMSY is located in a suburban area, so urban heat effects are less pronounced than they would be at a downtown station, but surrounding development still elevates temperatures slightly.

Record High: 102°F recorded on August 22, 1980.

Record Low: 6°F recorded on February 13, 1899.

Historical Note: New Orleans rarely sees temperature extremes due to the moderating Gulf influence. Readings above 100°F occur only a few times per decade, and hard freezes are similarly rare events.