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Annually, the Earth experiences an average of approximately one meter (39 inches) of rainfall or snowfall. Nevertheless, differences in latitude, wind patterns, alterations in the Earth’s topography, and the planet’s axial tilt contribute to an uneven dispersion of precipitation worldwide.
In his cartographic work, Perrin Remonté employs data sourced from Chelsea Climate to illustrate this phenomenon by dividing the globe into two distinct halves. The first half, depicted in blue, encounters an annual precipitation of more than one meter (whether in the form of rain or snow), while the second half receives a lesser amount.
Global precipitation patterns are shaped by a multitude of factors, each playing a significant role in determining the distribution of rainfall and snowfall across the planet:
Closeness to water bodies: Oceans and lakes serve as a continuous reservoir of moisture.
Latitude: Proximity to the equator impacts the amount of sunlight received, affecting temperature and evaporation rates. Consequently, regions near the equator often experience more frequent and intense precipitation.
Wind Patterns: Atmospheric circulation guides the movement of air masses, creating convergence zones where rising air results in increased precipitation.
Topography: The presence of mountains alters precipitation by forcing air to rise, cool, and release moisture. Windward slopes typically receive more rainfall, while the leeward side may experience a rain shadow effect.
Ocean Currents: Warm ocean currents contribute to higher evaporation rates, increasing humidity and influencing precipitation in adjacent coastal areas.
Temperature: Warmer air holds more moisture, leading to elevated evaporation rates and the potential for increased precipitation.
Seasonal Changes: Earth’s axial tilt and orbital variations cause seasonal shifts, impacting temperature and precipitation patterns throughout the year.
Climate Change: Human-induced climate change is modifying global climate dynamics, affecting precipitation through changes in sea surface temperatures, melting ice, and shifts in atmospheric circulation.
Natural Climate Phenomena: Events like El Niño and La Niña in the Pacific Ocean exert influence on global weather patterns, impacting precipitation in diverse regions.
Vegetation and Land Use: Different land covers, such as forests or urban areas, can influence local precipitation. Vegetation, through transpiration, releases moisture into the atmosphere, influencing humidity levels.
The Wettest and Driest Places in the World
The wettest places on Earth are often found in tropical rainforests and equatorial regions. Examples include the Amazon Rainforest in South America, the Congo Basin in Africa, and parts of Southeast Asia, like the Mawsynram region in India, which receives exceptionally high rainfall due to the influence of monsoons and proximity to warm ocean currents.
The 10 Wettest Places in the World
Rank
Place
Average Precipitation, mm
1
Colombia López de Micay, Colombia
15,992
2
Mawsynram, Meghalaya State, India
11,871
3
Cherrapunji, Meghalaya State, India
11,777
4
Tutendo, Colombia, South America
11,770
5
Cropp River, New Zealand
11,516
6
San Antonio de Ureca, Bioko Island, Equatorial Guinea
10,450
7
Debundscha, Cameroon, Africa
10,299
8
Big Bog, Maui, Hawaii
10,272
9
Mt Waialeale, Kauai, Hawaii
9,763
10
Kukui, Maui, Hawaii
9,445
The driest places on Earth are primarily located in subtropical deserts, such as the Atacama Desert in South America, the Sahara Desert in Africa, and the Arabian Desert in the Middle East. These regions experience low precipitation due to descending air masses and high-pressure systems.
Nevertheless, the driest place on the planet is considered to be the Dry Valleys of Antarctica. The valleys exhibit extremely low humidity and are virtually devoid of ice or snow, making them the largest ice-free region on the continent. Adjacent mountains, towering in height, act as a barrier preventing ice from the sea from reaching the valleys. These distinctive conditions result, in part, from the influence of potent katabatic winds, which occur when cold, dense air descends downhill under the force of gravity. With speeds reaching up to 200 mph (322 kph), these winds heat up as they descend, causing the evaporation of all water, ice, and snow. Remarkably resembling the conditions on Mars, these valleys are considered Earth’s environments closest to the Red Planet, prompting scientists to study the ecosystem for insights into the Martian surface.
The 10 Driest Places in the World
Rank
Place
Average Precipitation, mm
1
Dry Valleys, Antarctica
0
2
Arica, Chile
0.761
3
Al-Kufrah, Libya
0.860
4
Aswan, Egypt
0.861
5
Luxor, Egypt
0.862
6
Ica, Peru
2.29
7
Wadi Halfa, Sudan
2.45
8
Iquique, Chile
5.08
9
Pelican Point, Namibia
8.13
10
Aoulef, Algeria
12.19
Countries Experiencing the Highest and Lowest Precipitation
Based on 2020 World Bank data, Colombia claimed the highest position on the list, receiving 3,240 millimeters (125.8 inches) of rainfall annually. This can be attributed to its location on the equator, proximity to the Intertropical Convergence Zone, presence of the Andes mountain range, and two coastlines.
Nations located close to the equator or possessing substantial coastlines, factors contributing to elevated levels of rainfall occupy the subsequent 10 positions on the list.
Top 10 Countries Experiencing the Highest Precipitation
Rank
Country
Average Precipitation, mm
1
Colombia
3,240
2
Sao Tome & Principe
3,200
3
Papua New Guinea
3,142
4
Solomon Islands
3,028
5
Panama
2,928
6
Costa Rica
2,926
7
Samoa
2,880
8
Malaysia
2,875
9
Brunei Darussalam
2,722
10
Indonesia
2,702
Nevertheless, North African countries, such as Egypt and Libya, exhibit arid climates despite their coastal locations. This is attributed to high-pressure weather systems inhibiting the ascent of moist air, mountains creating rain shadows, and cold ocean currents diminishing consistent evaporation. Furthermore, the region falls within the 30-degree latitude band around the equator, where atmospheric conditions contribute to drier environments, ultimately giving rise to desert conditions.
Top 10 Countries with the Least Precipitation
Rank
Country
Average Precipitation, mm
1
Egypt
18
2
Libya
56
3
Saudi Arabia
59
4
Qatar
74
5
UAE
78
6
Bahrain
83
7
Algeria
89
8
Mauritania
92
9
Jordan
111
10
Kuwait
121
On the map below, countries where the average annual precipitation is lower than the global annual average (1 meter) are colored yellow, orange, and red.
Nations where the average annual precipitation is higher than the global annual average are shown in blue. Below is animated version of map.
You can learn more about the climate from the following map posters:
