Climate and Average Weather Year Round in Blama Sierra Leone

In Blama, the wet season is warm, oppressive, and overcast and the dry season is hot, muggy, and partly cloudy. Over the course of the year, the temperature typically varies from 67°F to 93°F and is rarely below 60°F or above 99°F.

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

The hot season lasts for 2.6 months, from February 1 to April 20, with an average daily high temperature above 91°F. The hottest month of the year in Blama is March, with an average high of 93°F and low of 74°F.

The cool season lasts for 3.4 months, from June 29 to October 10, with an average daily high temperature below 84°F. The coldest month of the year in Blama is August, with an average low of 71°F and high of 82°F.

In Blama, 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 Blama begins around November 19 and lasts for 3.6 months, ending around March 6.

The clearest month of the year in Blama is January, during which on average the sky is clear, mostly clear, or partly cloudy 63% of the time.

The cloudier part of the year begins around March 6 and lasts for 8.4 months, ending around November 19.

The cloudiest month of the year in Blama is May, during which on average the sky is overcast or mostly cloudy 77% 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 Blama varies very significantly throughout the year.

The wetter season lasts 5.9 months, from April 30 to October 27, with a greater than 45% chance of a given day being a wet day. The month with the most wet days in Blama is August, with an average of 26.4 days with at least 0.04 inches of precipitation.

The drier season lasts 6.1 months, from October 27 to April 30. The month with the fewest wet days in Blama is January, with an average of 0.9 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 Blama is August, with an average of 26.4 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 87% on August 28.

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. Blama experiences extreme seasonal variation in monthly rainfall.

The rainy period of the year lasts for 10 months, from February 12 to December 21, with a sliding 31-day rainfall of at least 0.5 inches. The month with the most rain in Blama is August, with an average rainfall of 17.4 inches.

The rainless period of the year lasts for 1.7 months, from December 21 to February 12. The month with the least rain in Blama is January, with an average rainfall of 0.2 inches.

The length of the day in Blama does not vary substantially over the course of the year, staying within 34 minutes of 12 hours throughout. In 2024, the shortest day is December 21, with 11 hours, 40 minutes of daylight; the longest day is June 20, with 12 hours, 35 minutes of daylight.

The earliest sunrise is at 6:26 AM on May 25, and the latest sunrise is 39 minutes later at 7:05 AM on January 30. The earliest sunset is at 6:22 PM on November 13, and the latest sunset is 45 minutes later at 7:07 PM on July 14.

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

Blama experiences significant seasonal variation in the perceived humidity.

The muggier period of the year lasts for 11 months, from February 2 to December 20, during which time the comfort level is muggy, oppressive, or miserable at least 63% of the time.

The month with the fewest muggy days in Blama is January, with 16.7 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 Blama experiences significant seasonal variation over the course of the year.

The windier part of the year lasts for 3.4 months, from June 13 to September 25, with average wind speeds of more than 5.4 miles per hour. The windiest month of the year in Blama is August, with an average hourly wind speed of 7.0 miles per hour.

The calmer time of year lasts for 8.6 months, from September 25 to June 13. The calmest month of the year in Blama is November, with an average hourly wind speed of 3.7 miles per hour.

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

The wind is most often from the west for 3.7 months, from January 24 to May 15 and for 2.4 weeks, from November 12 to November 29, with a peak percentage of 52% on April 4. The wind is most often from the south for 5.9 months, from May 15 to November 12, with a peak percentage of 65% on July 15. The wind is most often from the east for 1.8 months, from November 29 to January 24, with a peak percentage of 42% on January 1.

Blama 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 water temperature does not vary significantly over the course of the year, remaining within 2°F of 82°F throughout.

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

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 Blama for hot-weather activities is from late November to mid February, with a peak score in the first week of January.

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 Blama 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 2.1 months, from January 7 to March 11, with an average daily incident shortwave energy per square meter above 5.3 kWh. The brightest month of the year in Blama is February, with an average of 5.5 kWh.

The darker period of the year lasts for 1.7 months, from April 29 to June 20, with an average daily incident shortwave energy per square meter below 4.5 kWh. The darkest month of the year in Blama is May, with an average of 4.3 kWh.

For the purposes of this report, the geographical coordinates of Blama are 7.875 deg latitude, -11.345 deg longitude, and 400 ft elevation.

The topography within 2 miles of Blama contains only modest variations in elevation, with a maximum elevation change of 417 feet and an average elevation above sea level of 443 feet. Within 10 miles contains only modest variations in elevation (1,795 feet). Within 50 miles contains very significant variations in elevation (2,723 feet).

The area within 2 miles of Blama is covered by cropland (41%), grassland (22%), trees (20%), and shrubs (16%), within 10 miles by cropland (36%) and trees (28%), and within 50 miles by trees (40%) and cropland (30%).