⏱ 4 min read
Nepal’s climate changes from tropical heat in the Terai to arctic cold on the Himalayan peaks, all within a short distance. Lok Sewa asks about climatic zones, the monsoon, the wettest and driest places, rain shadow areas and the six seasons of the Nepali calendar. This note covers each of these with the key facts and numbers.
1. What controls Nepal’s climate?
- Altitude is the most important factor: temperature falls by about 6.5 °C for every 1,000 m of height.
- Latitude: Nepal lies roughly between 26° and 30° north, in the subtropical belt.
- Monsoon winds from the Bay of Bengal bring most of the rain.
- The Himalaya blocks cold winds from Central Asia and stops monsoon clouds, creating rain shadow areas to the north.
- Slope direction: south-facing slopes get more sun and rain than north-facing slopes.
2. Climatic zones by altitude
| Zone | Approximate altitude | Where |
|---|---|---|
| Tropical | Below 1,000 m | Terai, Chure foothills, inner Terai |
| Subtropical | 1,000 to 2,000 m | Lower hills and valleys |
| Temperate | 2,000 to 3,000 m | Middle mountains, e.g. upper hills |
| Subalpine | 3,000 to 4,000 m | High hills and lower Himalaya |
| Alpine | 4,000 to 5,000 m | High Himalaya pastures |
| Tundra / arctic | Above 5,000 m | Permanent snow and ice |
3. Monsoon and rainfall
- About 80% of Nepal’s annual rain falls in the summer monsoon (June to September).
- The monsoon comes from the Bay of Bengal, enters Nepal from the east around mid-June and leaves by early October.
- So eastern Nepal gets more summer rain than western Nepal, and the monsoon arrives in the west later.
- Winter rain comes from western disturbances (originating near the Mediterranean), so western Nepal gets more winter rain and snow.
- In the Terai, winter brings dense fog and cold waves (sheetlahar); pre-monsoon months bring heat waves and thunderstorms.
| Feature | Place |
|---|---|
| Wettest place (highest annual rainfall) | Lumle, Kaski |
| Driest place (lowest rainfall) | Lo Manthang, Mustang |
| Rain shadow areas | Mustang, Manang and Dolpa (north of the Himalaya) |
| Among the hottest places | Nepalgunj, Dhangadhi and Bhairahawa in the Terai |
4. Six seasons (ritu) of Nepal
| Season (ritu) | Nepali months | Character |
|---|---|---|
| Basanta (spring) | Chaitra and Baisakh | Pleasant, flowers bloom |
| Grishma (summer) | Jestha and Asar | Hot; monsoon begins |
| Barsha (rainy) | Shrawan and Bhadra | Heavy rain, floods and landslides |
| Sharad (autumn) | Ashwin and Kartik | Clear sky; Dashain and Tihar |
| Hemanta (pre-winter) | Mangsir and Poush | Cool and dry; harvest |
| Shishir (winter) | Magh and Falgun | Coldest; fog in the Terai |
5. Climate change and weather services
- Weather forecasting in Nepal is done by the Department of Hydrology and Meteorology (DHM).
- Temperature in the Himalaya is rising faster than the global average, causing glacier melt and risk of glacial lake outburst floods (GLOFs).
- Changes in rainfall cause drought in some places and floods and landslides in others.
6. Facts table
| Fact | Detail |
|---|---|
| Wettest place | Lumle, Kaski |
| Driest areas | Mustang and Manang (rain-shadow areas) |
| Monsoon arrives | From the east, usually around mid-June |
| Share of rain from monsoon | About 80% of yearly rainfall |
| Hottest areas | Terai, such as Nepalgunj and Dhangadhi |
| Weather agency | Department of Hydrology and Meteorology |
7. Effects of climate change in Nepal
- Glaciers are retreating and glacial lakes are growing, raising the risk of GLOFs.
- More intense rain causes floods and landslides.
- Changing rainfall patterns affect paddy planting and other crops.
- Warmer temperatures spread mosquito-borne diseases such as dengue to higher areas.
8. How this topic is asked in the exam
Objective questions ask the wettest and driest places, when the monsoon arrives, the six seasons (ritu) and the climatic zones by altitude. Subjective questions ask about the impact of climate change on Nepal. Give examples from agriculture, water and disasters.
📌 Key points to remember
- Altitude is the main factor; temperature falls about 6.5 °C per 1,000 m.
- Zones: tropical (<1,000 m), subtropical, temperate, subalpine, alpine, tundra (>5,000 m).
- About 80% of rain falls in the summer monsoon from the Bay of Bengal.
- Monsoon enters from the east; east gets more summer rain, west more winter rain.
- Winter rain comes from western disturbances.
- Wettest: Lumle (Kaski); driest: Lo Manthang (Mustang).
- Rain shadow: Mustang, Manang, Dolpa.
- Six ritu: Basanta, Grishma, Barsha, Sharad, Hemanta, Shishir.
- Weather service: Department of Hydrology and Meteorology.
📝 Quiz
Test yourself: Climate and Seasons of Nepal
Practise What controls Nepal’s climate?, Monsoon and rainfall and Climate change and weather services with 50 questions. Each attempt picks 25 at random.
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