Climate and Average Weather Year Round in Chattanooga Tennessee, United States
In Chattanooga, the summers are hot and muggy; the winters are short, very cold, and wet; and it is partly cloudy year round. Over the course of the year, the temperature typically varies from 33°F to 89°F and is rarely below 19°F or above 96°F.
Based on the tourism score, the best times of year to visit Chattanooga for warm-weather activities are from mid May to mid June and from mid August to early October.
Climate in Chattanooga
The hot season lasts for 3.8 months, from May 25 to September 19, with an average daily high temperature above 81°F. The hottest month of the year in Chattanooga is July, with an average high of 89°F and low of 70°F.
The cool season lasts for 2.9 months, from November 28 to February 25, with an average daily high temperature below 58°F. The coldest month of the year in Chattanooga is January, with an average low of 33°F and high of 50°F.
Average High and Low Temperature in Chattanooga
The figure below shows you a compact characterization of the entire year of hourly average temperatures. The horizontal axis is the day of the year, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.
Average Hourly Temperature in Chattanooga
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
Shkodër, Albania (5,308 miles away); Kafr Takhārīm, Syria (6,266 miles); and Luoqiao, China (7,908 miles) are the far-away foreign places with temperatures most similar to Chattanooga (view comparison).
In Chattanooga, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.
The clearer part of the year in Chattanooga begins around June 13 and lasts for 5.2 months, ending around November 20.
The clearest month of the year in Chattanooga is September, during which on average the sky is clear, mostly clear, or partly cloudy 65% of the time.
The cloudier part of the year begins around November 20 and lasts for 6.8 months, ending around June 13.
The cloudiest month of the year in Chattanooga is January, during which on average the sky is overcast or mostly cloudy 54% of the time.
Cloud Cover Categories in Chattanooga
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Chattanooga varies throughout the year.
The wetter season lasts 5.1 months, from March 20 to August 23, with a greater than 32% chance of a given day being a wet day. The month with the most wet days in Chattanooga is July, with an average of 12.9 days with at least 0.04 inches of precipitation.
The drier season lasts 6.9 months, from August 23 to March 20. The month with the fewest wet days in Chattanooga is October, with an average of 6.9 days with at least 0.04 inches of precipitation.
Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. The month with the most days of rain alone in Chattanooga is July, with an average of 12.9 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 44% on July 9.
Daily Chance of Precipitation in Chattanooga
To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. Chattanooga experiences significant seasonal variation in monthly rainfall.
Rain falls throughout the year in Chattanooga. The month with the most rain in Chattanooga is December, with an average rainfall of 4.7 inches.
The month with the least rain in Chattanooga is August, with an average rainfall of 2.8 inches.
Average Monthly Rainfall in Chattanooga
As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day of the year. Chattanooga experiences some seasonal variation in monthly snowfall.
The snowy period of the year lasts for 1.2 months, from January 1 to February 9, with a sliding 31-day snowfall of at least 1.0 inches. The month with the most snow in Chattanooga is January, with an average snowfall of 1.4 inches.
The snowless period of the year lasts for 11 months, from February 9 to January 1. The least snow falls around July 25, with an average total accumulation of 0.0 inches.
Average Monthly Snowfall in Chattanooga
The length of the day in Chattanooga varies significantly over the course of the year. In 2023, the shortest day is December 21, with 9 hours, 48 minutes of daylight; the longest day is June 21, with 14 hours, 31 minutes of daylight.
Hours of Daylight and Twilight in Chattanooga
The earliest sunrise is at 6:26 AM on June 12, and the latest sunrise is 1 hour, 38 minutes later at 8:04 AM on November 4. The earliest sunset is at 5:29 PM on December 5, and the latest sunset is 3 hours, 30 minutes later at 8:59 PM on June 29.
Daylight saving time (DST) is observed in Chattanooga during 2023, starting in the spring on March 12, lasting 7.8 months, and ending in the fall on November 5.
Sunrise & Sunset with Twilight and Daylight Saving Time in Chattanooga
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.
Solar Elevation and Azimuth in Chattanooga
The figure below presents a compact representation of key lunar data for 2023. 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.
Moon Rise, Set & Phases in Chattanooga
We 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.
Chattanooga experiences extreme seasonal variation in the perceived humidity.
The muggier period of the year lasts for 4.3 months, from May 20 to September 28, during which time the comfort level is muggy, oppressive, or miserable at least 21% of the time. The month with the most muggy days in Chattanooga is July, with 25.2 days that are muggy or worse.
The month with the fewest muggy days in Chattanooga is February, with 0.0 days that are muggy or worse.
Humidity Comfort Levels in Chattanooga
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
This 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 Chattanooga experiences mild seasonal variation over the course of the year.
The windier part of the year lasts for 6.5 months, from October 27 to May 12, with average wind speeds of more than 4.4 miles per hour. The windiest month of the year in Chattanooga is March, with an average hourly wind speed of 5.5 miles per hour.
The calmer time of year lasts for 5.5 months, from May 12 to October 27. The calmest month of the year in Chattanooga is August, with an average hourly wind speed of 3.3 miles per hour.
Average Wind Speed in Chattanooga
The predominant average hourly wind direction in Chattanooga varies throughout the year.
The wind is most often from the north for 1.2 months, from January 19 to February 24 and for 2.3 weeks, from July 29 to August 14, with a peak percentage of 35% on January 29. The wind is most often from the south for 4.2 months, from February 24 to June 29 and for 5.2 months, from August 14 to January 19, with a peak percentage of 42% on May 4. The wind is most often from the west for 1.0 months, from June 29 to July 29, with a peak percentage of 35% on July 14.
Wind Direction in Chattanooga
To characterize how pleasant the weather is in Chattanooga throughout the year, we compute two travel scores.
The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best times of year to visit Chattanooga for general outdoor tourist activities are from mid May to mid June and from mid August to early October, with a peak score in the third week of September.
Tourism Score in Chattanooga
The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit Chattanooga for hot-weather activities is from mid June to early September, with a peak score in the second week of August.
Beach/Pool Score in Chattanooga
For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.
Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.
Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.
Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.
Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.
Definitions 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).
The growing season in Chattanooga typically lasts for 7.5 months (228 days), from around March 26 to around November 9, rarely starting before March 5 or after April 15, and rarely ending before October 22 or after November 28.
Time Spent in Various Temperature Bands and the Growing Season in Chattanooga
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
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.
Based on growing degree days alone, the first spring blooms in Chattanooga should appear around February 21, only rarely appearing before February 4 or after March 10.
Growing Degree Days in Chattanooga
This 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 experiences significant seasonal variation over the course of the year.
The brighter period of the year lasts for 4.6 months, from April 14 to September 2, with an average daily incident shortwave energy per square meter above 5.8 kWh. The brightest month of the year in Chattanooga is June, with an average of 6.6 kWh.
The darker period of the year lasts for 2.8 months, from November 12 to February 6, with an average daily incident shortwave energy per square meter below 3.2 kWh. The darkest month of the year in Chattanooga is December, with an average of 2.4 kWh.
Average Daily Incident Shortwave Solar Energy in Chattanooga
For the purposes of this report, the geographical coordinates of Chattanooga are 35.046 deg latitude, -85.310 deg longitude, and 673 ft elevation.
The topography within 2 miles of Chattanooga contains only modest variations in elevation, with a maximum elevation change of 262 feet and an average elevation above sea level of 678 feet. Within 10 miles contains only modest variations in elevation (1,660 feet). Within 50 miles contains very significant variations in elevation (3,652 feet).
The area within 2 miles of Chattanooga is covered by artificial surfaces (94%), within 10 miles by trees (56%) and artificial surfaces (34%), and within 50 miles by trees (67%) and cropland (27%).
This report illustrates the typical weather in Chattanooga, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.
Temperature and Dew Point
There are 5 weather stations near enough to contribute to our estimation of the temperature and dew point in Chattanooga.
For each station, the records are corrected for the elevation difference between that station and Chattanooga according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.
The estimated value at Chattanooga is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Chattanooga and a given station.
The stations contributing to this reconstruction are:
To get a sense of how much these sources agree with each other, you can view a comparison of Chattanooga and the stations that contribute to our estimates of its temperature history and climate. Please note that each source's contribution is adjusted for elevation and the relative change present in the MERRA-2 data.
All 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.
The 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.
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