Climate of Northeast India: Characteristics, Types, Rainfall and Temperature
Northeast India has a predominantly tropical character, particularly in its valley regions. The region experiences a monsoon climate characterized by heavy to very heavy rainfall, concentrated mainly during the four summer months from June to September. The southwest monsoon is the principal source of rainfall, and June is generally the rainiest month.
The climate of Northeast India is strongly influenced by its geographical location, varied topography, altitude, mountain ranges, river valleys and the southwest monsoon. As a result, considerable climatic variations can be observed between the plains, valleys, foothills and high mountain areas.
Climate Characteristics of Northeast India
Northeast India generally experiences three major seasons—winter, summer and rainy season. As in much of India, the rainy season largely coincides with the summer months because of the influence of the southwest monsoon.
A marked climatic contrast exists between the valleys and mountainous regions. While the mean January temperature in the valley region of Assam is around 16°C, temperatures in the mountainous areas of Arunachal Pradesh and Nagaland are considerably lower. In the higher mountainous areas, winter temperatures may fall below 0°C.
During summer, temperatures in the plains generally range between 30°C and 33°C, whereas the hill regions have a much milder summer climate. The mean summer temperature in the hills is around 20°C, with an average minimum of approximately 15°C.
Heavy snowfall is generally absent from most parts of Northeast India. However, snowfall occurs in the higher elevations of Arunachal Pradesh, particularly in areas such as West Kameng and Tawang.
Rainfall in Northeast India
Rainfall is one of the most important characteristics of the climate of Northeast India. The region receives some of the highest rainfall in India, mainly because of the southwest monsoon and the orographic effects of the surrounding mountain systems.
No major part of Northeast India receives annual rainfall below 1,000 mm. The Meghalaya Plateau, particularly its southern edge, receives exceptionally heavy rainfall. The steep southern escarpment overlooking the plains of Bangladesh plays an important role in forcing moisture-laden monsoon winds to rise and produce intense rainfall.
Cherrapunji, located near this southern escarpment, is famous for its extremely high rainfall and has an average annual rainfall of about 11,465 mm according to the figures cited in the reference material.
The Brahmaputra Valley receives an average annual rainfall of around 2,000 mm, although there are considerable local variations.
Guwahati, which lies partly under the rain-shadow influence of the Meghalaya Plateau, receives comparatively less rainfall, with an annual average of about 1,717 mm.
Approximately 90% of the annual rainfall is received during the southwest summer monsoon, with June being the rainiest month.
The hilly areas of Northeast India generally receive between 2,000 and 3,000 mm of rainfall. However, certain locations such as Kohima in Nagaland and Imphal in Manipur receive less than 2,000 mm because of their relative location in the rain-shadow areas of surrounding mountains.
Factors Influencing the Climate of Northeast India
The climate of Northeast India is influenced by several important geographical factors:
1. Geographical Location
The region lies in the northeastern part of India and is influenced strongly by the seasonal monsoon circulation. Its position contributes to the predominantly tropical and monsoonal character of the climate.
2. Relief and Topography
The presence of the Himalayas, Patkai ranges, Naga Hills, Khasi-Jaintia Hills, Mizo Hills and other mountainous systems significantly influences temperature, rainfall and local climatic conditions.
3. Altitude
Temperature decreases with increasing altitude. Consequently, the highlands of Arunachal Pradesh and other mountainous regions experience much cooler conditions than the low-lying plains and valleys.
4. Southwest Monsoon
The southwest monsoon is the principal source of rainfall. Moisture-laden winds produce widespread and heavy rainfall after interacting with the region's mountains and plateaus.
5. Rain-Shadow Effect
Mountain barriers create significant local differences in rainfall. Some areas receive extremely heavy rainfall, while locations situated behind mountain ranges receive comparatively lower rainfall.
Types of Climate Found in Northeast India
The varied relief and altitude of Northeast India have resulted in the development of several distinct climatic types. The following five broad types can be identified:
1. Cloud, Humid, High-Altitude Climate
This type of climate prevails over the mid-northern part of Arunachal Pradesh and the eastern hills at elevations above approximately 2,000 metres.
The temperature is generally low. Winter temperatures may fall below 0°C, while even during the hottest months temperatures generally do not exceed about 20°C.
Precipitation is high and may occur partly in the form of snowfall during winter. The average annual precipitation is generally above 150 cm.
Because of the mountainous terrain and harsh climatic conditions, agricultural opportunities are limited. Some hill rice, maize, millets and vegetables are cultivated on suitable mountain slopes.
2. Humid Sub-Tropical Monsoon Climate
This climatic type occurs over the foothills of Arunachal Pradesh bordering the Brahmaputra Valley, Nagaland, the eastern part of the North Cachar Hills, Manipur and Mizoram.
Temperatures are higher than those of the high-altitude regions but lower than those of the plains. The average annual temperature generally ranges between approximately 10°C and 20°C according to the classification used in the reference material.
The summers are warm, humid and relatively long, while winters are comparatively longer and drier than in the plains.
The combination of moderate temperatures and substantial rainfall supports a variety of agricultural activities in suitable locations.
3. Hot, Humid Monsoon Climate
This climatic type occurs throughout the plains of Northeast India and the northern foothills of Meghalaya.
Temperatures are generally higher than in the surrounding hill regions. Summer maximum temperatures may reach around 36°C, while winter minimum temperatures may remain around 10°C.
Rainfall is high, with average annual precipitation generally above 150 cm and reaching around 300 cm in many locations.
Relative humidity remains high for much of the year, particularly during the monsoon season.
This climate is especially favourable for agriculture because of the combination of warm temperatures, abundant rainfall and fertile valley soils.
4. Rainy, Cool Monsoon Climate
This type of climate prevails over the higher southern half of Meghalaya, particularly to the south of a line joining Darugiri, Nongkhlaw, Umsing and Hamren in Karbi Anglong.
The region is characterized by relatively low temperatures, with summer temperatures generally remaining below about 20°C and winter temperatures approaching 0°C in colder locations.
Rainfall occurs for approximately eight months of the year, and the average annual rainfall exceeds 250 cm.
This climatic region includes some of the rainiest places in the world, particularly Mawsynram.
Agriculture includes the cultivation of:
Hill rice
Rice
Maize
Millets
Vegetables
The region also supports a variety of fruits, including apples, oranges, pears, apricots and pineapples.
Natural pine forests are an important feature of this climatic region.
5. Alpine Climate
The alpine climate occurs in the high Himalayan region along the northern part of Arunachal Pradesh.
The area has a cold climate throughout the year, with temperatures remaining below 0°C for long periods during winter.
Cold mountain winds are common and may develop into blizzards during severe winter conditions. Precipitation occurs mainly in the form of snowfall during winter, while summer rainfall is comparatively limited.
Because the ground remains frozen for extended periods and summer rainfall is insufficient, natural vegetation is mainly restricted to:
Alpine grasses
Short bushes
Junipers
Stunted conifers
Agriculture is limited and is generally confined to sheltered valleys. Barley and oats may be grown in suitable areas.
Yaks and mules have traditionally been important domesticated animals and beasts of burden in the high mountain regions.
Climatic Contrast Between the Plains and Hills
One of the most important characteristics of Northeast India's climate is the strong contrast between its lowland plains and high mountain areas.
The Assam Valley and other low-lying areas experience warmer temperatures, while the mountainous regions of Arunachal Pradesh, Nagaland, Meghalaya, Manipur and Mizoram generally have cooler conditions because of elevation.
Similarly, rainfall varies greatly across short distances. The southern slopes of Meghalaya receive extremely heavy rainfall, whereas some valleys and rain-shadow areas receive considerably less.
Thus, the climate of Northeast India is characterized by high rainfall, strong seasonal variation, altitudinal temperature differences and considerable local climatic diversity.
Importance of the Climate of Northeast India
The climate of Northeast India has a direct influence on the region's agriculture, forests, biodiversity, water resources and economic activities.
Heavy monsoon rainfall supports:
Extensive river systems
Forest growth
Paddy cultivation
Tea cultivation
Horticulture
Bamboo and cane resources
Rich biodiversity
At the same time, excessive rainfall can contribute to floods, soil erosion, landslides and other natural hazards, particularly during periods of intense monsoon activity.
The climatic diversity of the region also creates favourable conditions for growing a wide variety of crops and supporting diverse natural ecosystems.
Conclusion
The climate of Northeast India is predominantly monsoonal and varies significantly according to altitude, relief and geographical location. The valleys generally experience a warm and humid tropical climate, while the mountainous regions have cooler and, at higher elevations, alpine conditions.
The southwest monsoon is the principal source of rainfall, and most of the annual precipitation occurs between June and September. The region is also notable for some of the highest rainfall zones in the world, especially in Meghalaya.
From the hot and humid plains of Assam to the cool mountain climate of Meghalaya and the alpine conditions of northern Arunachal Pradesh, Northeast India displays remarkable climatic diversity within a relatively compact geographical region.
Frequently Asked Questions (FAQs)
What type of climate is found in Northeast India?
Northeast India mainly experiences a tropical and monsoon climate, although considerable variations occur because of differences in altitude, relief and geographical location.
Which monsoon brings most of the rainfall to Northeast India?
The southwest monsoon is the principal source of rainfall in Northeast India.
Which month receives the highest rainfall in Northeast India?
June is generally considered the rainiest month across much of Northeast India.
Why does Northeast India receive heavy rainfall?
The region receives heavy rainfall mainly because of moisture-laden southwest monsoon winds and the orographic effect of mountains and plateaus.
Which part of Northeast India receives the highest rainfall?
The southern part of Meghalaya, particularly around Mawsynram and Cherrapunji, receives exceptionally high rainfall.
Does it snow in Northeast India?
Snowfall occurs mainly in the higher mountainous areas of Arunachal Pradesh, especially in places such as Tawang and other high-altitude regions.
What are the major climatic types of Northeast India?
Five broad climatic types described in the reference material are:
Cloud, Humid, High-Altitude Climate
Humid Sub-Tropical Monsoon Climate
Hot, Humid Monsoon Climate
Rainy, Cool Monsoon Climate
Alpine Climate