Spring Weather in Key West Florida, United StatesDaily high temperatures increase by 9°F, from 77°F to 86°F, rarely falling below 70°F or exceeding 89°F. Daily low temperatures increase by 10°F, from 68°F to 78°F, rarely falling below 60°F or exceeding 81°F. For reference, on August 6, the hottest day of the year, temperatures in Key West typically range from 81°F to 89°F, while on January 18, the coldest day of the year, they range from 65°F to 74°F. The figure below shows you a compact characterization of the hourly average spring temperatures. The horizontal axis is the day, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day. Hengchun, Taiwan (8,892 miles away) is the far-away foreign place with temperatures most similar to Key West (view comparison). CloudsThe spring in Key West experiences very rapidly increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 29% to 57%. The lowest chance of overcast or mostly cloudy conditions is 27% on March 5. The clearest day of the spring is March 5, with clear, mostly clear, or partly cloudy conditions 73% of the time. For reference, on June 19, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 70%, while on March 5, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 73%. PrecipitationA wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Key West, the chance of a wet day over the course of the spring is very rapidly increasing, starting the season at 14% and ending it at 45%. For reference, the year's highest daily chance of a wet day is 59% on September 15, and its lowest chance is 12% on March 19. RainfallTo show variation within the season and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day. The average sliding 31-day rainfall during the spring in Key West is very rapidly increasing, starting the season at 1.6 inches, when it rarely exceeds 3.8 inches, and ending the season at 5.2 inches, when it rarely exceeds 10.7 inches or falls below 1.4 inches. The lowest average 31-day accumulation is 1.4 inches on March 28. SunOver the course of the spring in Key West, the length of the day is rapidly increasing. From the start to the end of the season, the length of the day increases by 1 hour, 53 minutes, implying an average daily increase of 1 minute, 14 seconds, and weekly increase of 8 minutes, 40 seconds. The shortest day of the spring is March 1, with 11 hours, 41 minutes of daylight and the longest day is May 31, with 13 hours, 33 minutes of daylight. The latest sunrise of the spring in Key West is 7:40 AM on March 10 and the earliest sunrise is 1 hour, 2 minutes earlier at 6:38 AM on May 31. The earliest sunset is 6:29 PM on March 1 and the latest sunset is 1 hour, 42 minutes later at 8:11 PM on May 31. Daylight saving time (DST) starts at 3:00 AM on March 10, 2024, shifting sunrise and sunset to be an hour later. For reference, on June 20, the longest day of the year, the Sun rises at 6:39 AM and sets 13 hours, 40 minutes later, at 8:18 PM, while on December 21, the shortest day of the year, it rises at 7:07 AM and sets 10 hours, 37 minutes later, at 5:44 PM. The figure below presents a compact representation of the sun's elevation (the angle of the sun above the horizon) and azimuth (its compass bearing) for every hour of every day in the reporting period. The horizontal axis is the day of the year and the vertical axis is the hour of the day. For a given day and hour of that day, the background color indicates the azimuth of the sun at that moment. The black isolines are contours of constant solar elevation. MoonThe figure below presents a compact representation of key lunar data for the spring of 2024. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases. The label associated with each bar indicates the date and time that the phase is obtained, and the companion time labels indicate the rise and set times of the Moon for the nearest time interval in which the moon is above the horizon. HumidityWe base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night. The chance that a given day will be muggy in Key West is very rapidly increasing during the spring, rising from 48% to 97% over the course of the season. For reference, on July 2, the muggiest day of the year, there are muggy conditions 100% of the time, while on January 29, the least muggy day of the year, there are muggy conditions 42% of the time. WindThis section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages. The average hourly wind speed in Key West is rapidly decreasing during the spring, decreasing from 13.3 miles per hour to 10.7 miles per hour over the course of the season. For reference, on November 6, the windiest day of the year, the daily average wind speed is 14.6 miles per hour, while on July 28, the calmest day of the year, the daily average wind speed is 9.3 miles per hour. The hourly average wind direction in Key West throughout the spring is predominantly from the east, with a peak proportion of 68% on May 14. Water TemperatureKey West is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water. The average surface water temperature in Key West is rapidly increasing during the spring, rising by 8°F, from 74°F to 82°F, over the course of the season. Growing SeasonDefinitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere). Temperatures in Key West are sufficiently warm year round that it is not entirely meaningful to discuss the growing season in these terms. We nevertheless include the chart below as an illustration of the distribution of temperatures experienced throughout the year. Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F. The average accumulated growing degree days in Key West are very rapidly increasing during the spring, increasing by 2,436°F, from 1,200°F to 3,636°F, over the course of the season. Solar EnergyThis section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation. The average daily incident shortwave solar energy in Key West is essentially constant during the spring, remaining within 0.6 kWh of 6.2 kWh throughout. The highest average daily incident shortwave solar energy during the spring is 6.9 kWh on April 28. TopographyFor the purposes of this report, the geographical coordinates of Key West are 24.555 deg latitude, -81.782 deg longitude, and 3 ft elevation. The topography within 2 miles of Key West is essentially flat, with a maximum elevation change of 10 feet and an average elevation above sea level of 2 foot. Within 10 miles is also essentially flat (10 feet). Within 50 miles is also essentially flat (16 feet). The area within 2 miles of Key West is covered by water (59%) and artificial surfaces (37%), within 10 miles by water (95%), and within 50 miles by water (99%). Data SourcesThis report illustrates the typical weather in Key West, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016. Temperature and Dew PointThere is only a single weather station, Key West International Airport, in our network suitable to be used as a proxy for the historical temperature and dew point records of Key West. At a distance of 3 kilometers from Key West, closer than our threshold of 150 kilometers, this station is deemed sufficiently nearby to be relied upon as our primary source for temperature and dew point records. The station records are corrected for the elevation difference between the station and Key West according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations. Please note that the station records themselves may additionally have been back-filled using other nearby stations or the MERRA-2 reanalysis. Other DataAll data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Algorithms 2nd Edition , by Jean Meeus. All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid. Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations. Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory. Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database . Time zones for airports and weather stations are provided by AskGeo.com . Maps are © OpenStreetMap contributors. DisclaimerThe information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site. We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands. We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader. Please review our full terms contained on our Terms of Service page. |