Climate and Average Weather Year Round at Arusha Airport Tanzania

At Arusha Airport, the wet season is warm and overcast and the dry season is comfortable, windy, and partly cloudy. Over the course of the year, the temperature typically varies from 56°F to 83°F and is rarely below 52°F or above 88°F.

Based on the tourism score, the best time of year to visit Arusha Airport for warm-weather activities is from early July to early October.

The warm season lasts for 2.7 months, from January 2 to March 24, with an average daily high temperature above 81°F. The hottest month of the year at Arusha Airport is March, with an average high of 82°F and low of 62°F.

The cool season lasts for 3.2 months, from May 14 to August 20, with an average daily high temperature below 74°F. The coldest month of the year at Arusha Airport is July, with an average low of 56°F and high of 71°F.

At Arusha Airport, 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 at Arusha Airport begins around May 20 and lasts for 4.7 months, ending around October 10.

The clearest month of the year at Arusha Airport is August, during which on average the sky is clear, mostly clear, or partly cloudy 68% of the time.

The cloudier part of the year begins around October 10 and lasts for 7.3 months, ending around May 20.

The cloudiest month of the year at Arusha Airport is February, during which on average the sky is overcast or mostly cloudy 75% of the time.

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days at Arusha Airport varies significantly throughout the year.

The wetter season lasts 6.2 months, from November 11 to May 18, with a greater than 23% chance of a given day being a wet day. The month with the most wet days at Arusha Airport is April, with an average of 12.5 days with at least 0.04 inches of precipitation.

The drier season lasts 5.8 months, from May 18 to November 11. The month with the fewest wet days at Arusha Airport is July, with an average of 0.4 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 at Arusha Airport is April, with an average of 12.5 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 45% on April 19.

Rainfall

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. Arusha Airport experiences extreme seasonal variation in monthly rainfall.

The rainy period of the year lasts for 7.9 months, from October 9 to June 6, with a sliding 31-day rainfall of at least 0.5 inches. The month with the most rain at Arusha Airport is April, with an average rainfall of 4.4 inches.

The rainless period of the year lasts for 4.1 months, from June 6 to October 9. The month with the least rain at Arusha Airport is July, with an average rainfall of 0.1 inches.

The length of the day at Arusha Airport does not vary substantially over the course of the year, staying within 19 minutes of 12 hours throughout. In 2024, the shortest day is June 20, with 11 hours, 56 minutes of daylight; the longest day is December 21, with 12 hours, 19 minutes of daylight.

The earliest sunrise is at 6:09 AM on November 9, and the latest sunrise is 32 minutes later at 6:41 AM on July 21. The earliest sunset is at 6:23 PM on October 27, and the latest sunset is 31 minutes later at 6:54 PM on February 5.

Daylight saving time (DST) is not observed at Arusha Airport during 2024.

The figure below presents a compact representation of key lunar data for 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.

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.

Arusha Airport experiences some seasonal variation in the perceived humidity.

The muggier period of the year lasts for 5.9 months, from November 21 to May 19, during which time the comfort level is muggy, oppressive, or miserable at least 5% of the time. The month with the most muggy days at Arusha Airport is April, with 5.2 days that are muggy or worse.

The month with the fewest muggy days at Arusha Airport is July, with 0.0 days that are muggy or worse.

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 experiences significant seasonal variation over the course of the year.

The windier part of the year lasts for 7.1 months, from April 17 to November 19, with average wind speeds of more than 8.1 miles per hour. The windiest month of the year at Arusha Airport is September, with an average hourly wind speed of 10.9 miles per hour.

The calmer time of year lasts for 4.9 months, from November 19 to April 17. The calmest month of the year at Arusha Airport is January, with an average hourly wind speed of 5.3 miles per hour.

The predominant average hourly wind direction at Arusha Airport varies throughout the year.

The wind is most often from the south for 1.9 months, from May 27 to July 24, with a peak percentage of 57% on July 2. The wind is most often from the east for 10 months, from July 24 to May 27, with a peak percentage of 69% on January 1.

To characterize how pleasant the weather is at Arusha Airport 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 time of year to visit Arusha Airport for general outdoor tourist activities is from early July to early October, with a peak score in the first week of September.

The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best times of year to visit Arusha Airport for hot-weather activities are from early February to late March and from mid September to late November, with a peak score in the last week of October.

Methodology

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).

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.

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.

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 some seasonal variation over the course of the year.

The brighter period of the year lasts for 1.7 months, from September 5 to October 28, with an average daily incident shortwave energy per square meter above 7.3 kWh. The brightest month of the year at Arusha Airport is October, with an average of 7.4 kWh.

The darker period of the year lasts for 3.1 months, from April 26 to July 28, with an average daily incident shortwave energy per square meter below 6.5 kWh. The darkest month of the year at Arusha Airport is June, with an average of 6.2 kWh.