Climate and Average Weather Year Round in Zwedru Liberia

In Zwedru, the wet season is warm, oppressive, and mostly cloudy and the dry season is hot, muggy, and partly cloudy. Over the course of the year, the temperature typically varies from 68°F to 88°F and is rarely below 61°F or above 95°F.

Based on the beach/pool score, the best time of year to visit Zwedru for hot-weather activities is from late November to early February.

The temperature in Zwedru varies so little throughout the year that it is not entirely meaningful to discuss hot and cold seasons.

In Zwedru, 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 Zwedru begins around October 7 and lasts for 4.4 months, ending around February 18.

The clearest month of the year in Zwedru is December, during which on average the sky is clear, mostly clear, or partly cloudy 60% of the time.

The cloudier part of the year begins around February 18 and lasts for 7.6 months, ending around October 7.

The cloudiest month of the year in Zwedru is May, 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 in Zwedru varies very significantly throughout the year.

The wetter season lasts 7.6 months, from March 24 to November 12, with a greater than 42% chance of a given day being a wet day. The month with the most wet days in Zwedru is September, with an average of 22.2 days with at least 0.04 inches of precipitation.

The drier season lasts 4.4 months, from November 12 to March 24. The month with the fewest wet days in Zwedru is January, with an average of 2.9 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 Zwedru is September, with an average of 22.2 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 76% on September 29.

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. Zwedru experiences extreme seasonal variation in monthly rainfall.

Rain falls throughout the year in Zwedru. The month with the most rain in Zwedru is September, with an average rainfall of 8.9 inches.

The month with the least rain in Zwedru is January, with an average rainfall of 0.6 inches.

The length of the day in Zwedru does not vary substantially over the course of the year, staying within 28 minutes of 12 hours throughout. In 2024, the shortest day is December 21, with 11 hours, 46 minutes of daylight; the longest day is June 20, with 12 hours, 29 minutes of daylight.

The earliest sunrise is at 6:16 AM on May 23, and the latest sunrise is 34 minutes later at 6:50 AM on February 2. The earliest sunset is at 6:12 PM on November 11, and the latest sunset is 39 minutes later at 6:51 PM on July 15.

Daylight saving time (DST) is not observed in Zwedru 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.

Zwedru experiences significant seasonal variation in the perceived humidity.

The muggier period of the year lasts for 11 months, from January 29 to December 22, during which time the comfort level is muggy, oppressive, or miserable at least 75% of the time. The month with the most muggy days in Zwedru is May, with 31.0 days that are muggy or worse.

The month with the fewest muggy days in Zwedru is January, with 21.6 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 in Zwedru experiences significant seasonal variation over the course of the year.

The windier part of the year lasts for 3.6 months, from June 12 to October 1, with average wind speeds of more than 5.8 miles per hour. The windiest month of the year in Zwedru is August, with an average hourly wind speed of 7.4 miles per hour.

The calmer time of year lasts for 8.4 months, from October 1 to June 12. The calmest month of the year in Zwedru is November, with an average hourly wind speed of 4.3 miles per hour.

The predominant average hourly wind direction in Zwedru varies throughout the year.

The wind is most often from the south for 9.1 months, from March 19 to December 21, with a peak percentage of 82% on June 21. The wind is most often from the west for 2.9 months, from December 21 to March 19, with a peak percentage of 32% on January 1.

To characterize how pleasant the weather is in Zwedru 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 Zwedru for general outdoor tourist activities is from early December to late January, with a peak score in the last week of December.

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 Zwedru for hot-weather activities is from late November to early February, with a peak score in the last week of December.

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 in Zwedru 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.

For the purposes of this report, the geographical coordinates of Zwedru are 6.068 deg latitude, -8.136 deg longitude, and 725 ft elevation.

The topography within 2 miles of Zwedru contains only modest variations in elevation, with a maximum elevation change of 161 feet and an average elevation above sea level of 705 feet. Within 10 miles also contains only modest variations in elevation (433 feet). Within 50 miles contains only modest variations in elevation (2,195 feet).

The area within 2 miles of Zwedru is covered by grassland (31%), trees (24%), shrubs (24%), and cropland (21%), within 10 miles by trees (45%) and grassland (26%), and within 50 miles by trees (55%) and cropland (20%).