January Weather at Arusha Airport Tanzania
Daily high temperatures increase by 2°F, from 81°F to 83°F, rarely falling below 76°F or exceeding 88°F.
Daily low temperatures are around 60°F, rarely falling below 56°F or exceeding 63°F. The lowest daily average low temperature is 59°F on January 8.
For reference, on February 17, the hottest day of the year, temperatures at Arusha Airport typically range from 60°F to 83°F, while on July 14, the coldest day of the year, they range from 56°F to 71°F.
Average High and Low Temperature in January at Arusha Airport
The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on January. 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.
Average Hourly Temperature in January at Arusha Airport
The month of January at Arusha Airport experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 74% throughout the month.
The clearest day of the month is January 1, with clear, mostly clear, or partly cloudy conditions 28% of the time.
For reference, on February 2, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 76%, while on September 1, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 71%.
Cloud Cover Categories in January at Arusha Airport
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. At Arusha Airport, the chance of a wet day over the course of January is rapidly decreasing, starting the month at 26% and ending it at 18%.
For reference, the year's highest daily chance of a wet day is 45% on April 20, and its lowest chance is 1% on September 7.
Probability of Precipitation in January at Arusha Airport
To show variation within the month and not just the monthly total, we show the rainfall accumulated over a sliding 31-day period centered around each day.
The average sliding 31-day rainfall during January at Arusha Airport is decreasing, starting the month at 2.4 inches, when it rarely exceeds 6.0 inches or falls below 0.1 inches, and ending the month at 1.6 inches, when it rarely exceeds 4.1 inches or falls below 0.1 inches.
Average Monthly Rainfall in January at Arusha Airport
Over the course of January at Arusha Airport, the length of the day is essentially constant. The shortest day of the month is January 31, with 12 hours, 15 minutes of daylight and the longest day is January 1, with 12 hours, 19 minutes of daylight.
Hours of Daylight and Twilight in January at Arusha Airport
The earliest sunrise of the month at Arusha Airport is 6:27 AM on January 1 and the latest sunrise is 12 minutes later at 6:39 AM on January 31.
The earliest sunset is 6:46 PM on January 1 and the latest sunset is 8 minutes later at 6:54 PM on January 31.
Daylight saving time is not observed at Arusha Airport during 2021.
For reference, on December 21, the longest day of the year, the Sun rises at 6:21 AM and sets 12 hours, 19 minutes later, at 6:41 PM, while on June 21, the shortest day of the year, it rises at 6:37 AM and sets 11 hours, 56 minutes later, at 6:33 PM.
Sunrise & Sunset with Twilight in January at Arusha Airport
The figure below presents a compact representation of key lunar data for January 2021. 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.
Moon Rise, Set & Phases in January at Arusha Airport
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.
The chance that a given day will be muggy at Arusha Airport is gradually decreasing during January, falling from 10% to 8% over the course of the month.
The highest chance of a muggy day during January is 10% on January 5.
For reference, on April 9, the muggiest day of the year, there are muggy conditions 19% of the time, while on July 29, the least muggy day of the year, there are muggy conditions 0% of the time.
Humidity Comfort Levels in January at Arusha Airport
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 at Arusha Airport is essentially constant during January, remaining within 0.1 miles per hour of 5.4 miles per hour throughout.
For reference, on September 25, the windiest day of the year, the daily average wind speed is 11.0 miles per hour, while on January 29, the calmest day of the year, the daily average wind speed is 5.3 miles per hour.
The lowest daily average wind speed during January is 5.3 miles per hour on January 30.
Average Wind Speed in January at Arusha Airport
The hourly average wind direction at Arusha Airport throughout January is predominantly from the east, with a peak proportion of 69% on January 1.
Wind Direction in January at Arusha Airport
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).
Temperatures at Arusha Airport 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.
Time Spent in Various Temperature Bands and the Growing Season in January at Arusha Airport
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 at Arusha Airport are rapidly increasing during January, increasing by 612°F, from 3,143°F to 3,755°F, over the course of the month.
Growing Degree Days in January at Arusha Airport
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 at Arusha Airport is essentially constant during January, remaining within 0.1 kWh of 6.5 kWh throughout.
Average Daily Incident Shortwave Solar Energy in January at Arusha Airport
This report illustrates the typical weather at Arusha Airport, 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
Arusha Airport has a weather station that reported reliably enough during the analysis period that we have included it in our network. When available, historical temperature and dew point measurements are taken directly from this weather station. These records are obtained from NOAA's Integrated Surface Hourly data set, falling back on ICAO METAR records as required.
In the case of missing or erroneous measurements from this station, we fall back on records from nearby stations, adjusted according to typical seasonal and diurnal intra-station differences. For a given day of the year and hour of the day, the fallback station is selected to minimize the prediction error over the years for which there are measurements for both stations.
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 © Esri, with data from National Geographic, Esri, DeLorme, NAVTEQ, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, and iPC.
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.