Nepal Weather by Altitude
Himalayan Region Weather
Nepal's Himalayan region is characterized by diverse weather patterns, driven by its varied altitudes and geography, ranging from subtropical to alpine climates. Temperature and precipitation patterns show considerable regional variations, which impact both daily life and tourism activities.
Average Temperatures in the Himalayan Region
Average Annual Temperature: 4–8°C in the mountains, with temperatures below zero in higher altitudes year-round (Kumar, 2020).
Maximum Temperature: The annual mean maximum temperature varies from 4–8°C, with peaks reaching 12–16°C during the monsoon.
Minimum Temperature: The minimum temperature ranges from -6°C to -10°C, dropping below -10°C in winter.
Rainfall Trends
Average Rainfall: Varies from 50 mm to 5000 mm, with the central region receiving the highest (Dawadi et al., 2020).
Monsoon Dominance: Over 80% of Nepal’s annual rainfall occurs during the monsoon season (Phuyal et al., 2023), and it is the same for Himalayan Region.
Precipitation Trends: Post-monsoon rainfall is decreasing in recent years, while there is an increasing trend in rainfall in the far western and mountain regions.
Humidity: High humidity levels are common in areas like Sagarmatha National Park (Laiolo, 2004; Adhikari & Pradhananga, 2022).
Impact of Weather on Tourism
Trekking Hazards: Trekking and mountaineering are significantly affected by extreme weather conditions.
Khumbu Region: Weather is particularly unpredictable here, with clear mornings and drastic weather shifts in the afternoon (Paudel et al., 2022).
High Altitude Sickness: Weather conditions like temperature, wind speed, and air pressure are linked to the risk of altitude sickness.
Mount Everest: Trekkers to Everest Base Camp face extreme conditions like snowfalls, high winds, and rapid temperature changes (Adhikari & Pradhananga, 2022).
Operational Challenges: Unpredictable weather results in delays and increased operational costs for trekking expeditions, particularly at high altitudes where conditions can rapidly worsen (Adhikari & Pradhananga, 2022).
High Altitude Trekking Conditions
Khumbu Region: The alpine climate here experiences snow in winter and rain in summer (Adhikari & Pradhananga, 2022). Trekkers face risks from rock and ice falls, landslides, and altitude sickness, worsened by limited oxygen and extreme weather.
Crevasses: Crevasse risks are heightened in summer, particularly in alpine regions (Adhikari & Pradhananga, 2022).
Mid-Hills Region Weather
The Mid-Hills (Middle Mountains) of Nepal experience a temperate climate influenced by the varying altitudes and topography. This region is marked by distinct seasonal weather patterns, varying temperatures, and significant rainfall.
Temperature in Nepal's Mid-Hills
Average Temperatures:
Winter: Max temperature of 4-8°C, with lows dropping below 0°C at night.
Summer: Max temperature of 24-28°C, with highs reaching 21-28°C in lower elevations (Saha et al., 2024).
Elevation Impact:
Temperatures decrease with higher altitudes.
Diurnal temperature variations are more significant, especially in winter (Adhikari & Devkota, 2016).
The temperature lapse rate in the region is -0.51°C per 100 meters of altitude (Karki et al., 2015).
Rainfall Patterns
Annual Precipitation:
Average rainfall: Around 2700 mm annually, with Pokhara receiving over 5000 mm (Karki et al., 2016).
Monsoon (June-September): The wettest season, contributing the most to total rainfall (Joshi et al., 2019).
Precipitation Trends: Increasing rainfall during the pre-monsoon and monsoon seasons, with some regions showing more rainy days (Adhikari & Mathema, 2023).
Extreme Weather:
The western Mid-Hills are increasingly experiencing more extreme rainfall events (Talchabhadel et al., 2018).
Pokhara and Lumle receive some of the highest rainfall in Nepal (Adhikari & Mathema, 2023).
Seasonal Breakdown of Mid-Hills Climate
Pre-Monsoon (March-May): Increasing humidity and cloud formation (Sharma & Paudel, 2021).
Monsoon (June-September): Heavy rainfall, significantly affecting agriculture (Sharma & Paudel, 2021).
Post-Monsoon (October-November): Cooler and drier conditions.
Winter (December-February): Cold, dry conditions with occasional frost. Fog is common, especially in the valleys, but less intense than in the Terai (Shrestha, 2018).
Winds and Weather Phenomena
Winds: Strong diurnal winds are common, particularly in winter and spring, driven by thermal gradients (Bista, 2023).
Landslides: These are common during the monsoon season due to heavy rainfall (Awasthi & Owen, 2020).
Flooding: Flash floods in low-lying areas, especially during the monsoon (Kharel, 1997).
Fog: Frequent in lower valleys, especially in winter (Shrestha, 2018).
Hazards and Risks in the Mid-Hills
Landslides and Soil Erosion: Steep terrains are highly vulnerable to landslides during the monsoon (Kharel, 1997).
Unpredictable Weather: Weather variability disrupts daily life and agricultural activities (Adhikari & Devkota, 2016).
Tourism and Outdoor Activities
Best Seasons: Spring and autumn are ideal for outdoor activities like trekking, offering mild, stable weather (Laiolo, 2004).
Monsoon Challenges: Heavy rainfall disrupts trekking and outdoor activities (Kharel, 1997).
Weather Disruptions: Unpredictable weather can delay transportation, affecting the tourism experience (Kharel, 1997).
Key Climate Facts for the Mid-Hills:
Average temperature range: 4-8°C in winter to 24-28°C in summer.
Annual rainfall: 2700 mm, with regions like Pokhara receiving over 5000 mm.
Monsoon months: June-September are the wettest months.
Fog: Common in valleys during winter, especially in lower regions.
Warming trend: Increasing temperatures, especially at higher altitudes.
Terai Region Weather
The Terai region of Nepal, a flat plain at elevations of 60-200 meters above sea level, experiences a humid subtropical climate with distinct seasonal variations (Shrestha et al., 2018). This region is an extension of the Indo-Gangetic Plain, marked by hot, humid summers and mild winters, influencing daily life and agriculture significantly.
Temperature
Hot Summers: Average maximum temperatures range from 24-28°C, with peak temperatures reaching up to 35°C (Saha et al., 2024; Pranil, 2017).
Cool Winters: Temperatures drop to 5-10°C during winter months, with mild daytime conditions and colder nights (Shrestha et al., 2022; Kumarjit et al., 2024).
Daily Temperature Fluctuations: A decrease in daily temperature range is observed during winter due to frequent fog (Baidya et al., 2008).
Rainfall Patterns
Monsoon Influence: Over 80% of annual rainfall occurs during the monsoon season (June to September) (Shrestha et al., 2018; Sharma et al., 2021) throughout the country. This is also true for the Terai region.
Annual Rainfall: Total rainfall in the Terai region can range from 300-2700 mm (Kumarjit et al., 2024).
Westerly Winds: Besides the monsoon, winter rainfall is also influenced by westerly winds (Sharma et al., 2021).
Fog and Cold Waves
Fog: Dense fog is a common occurrence, especially from November to February, with peak fog events in December and January (Shrestha et al., 2018; Manandhar, 2006).
Visibility: Fog often reduces visibility to less than 200 meters, especially in the western Terai.
Duration: The region experiences 24-56 foggy days per year, with foggy hours ranging from 71 to 169 hours across different stations.
Cold Waves: The Terai experiences cold waves during December to February.
Cold wave days range from 9.2 to 13.8 days per year, with extreme cold waves occurring for 1.4 to 3.8 days annually (Shrestha et al., 2022).
Cold and extreme cold wave days are often coincident with foggy days, leading to a significant temperature drop.
Seasonal Characteristics
Winter (December - February): Cool with fog and cold waves.
Pre-Monsoon (March - May): Increasing temperatures and humidity.
Monsoon (June - September): Hot, humid, and rainy, with the heaviest rainfall.
Post-Monsoon (October - November): Cooler and drier, with a slight drop in humidity.
Summary Tables
Temperature across the 3 regions
Region | Winter Temperature | Summer Temperature | Annual Average Temperature |
Himalayan | -6°C to -10°C | 4°C to 16°C | 4–8°C |
Mid-Hills | 4°C to 8°C | 21°C to 28°C | 4–8°C (winter) to 24–28°C (summer) |
Terai | 5°C to 10°C | 24°C to 35°C | 24–28°C (summer), 5–10°C (winter) |
Rainfall patterns across the 3 regions
Region | Annual Rainfall | Monsoon Influence | Precipitation Trends |
Himalayan | 50 mm to 5000 mm | Over 80% of rainfall in monsoon | Decreasing post-monsoon, increasing in far west |
Mid-Hills | Around 2700 mm (Pokhara over 5000 mm) | Over 80% of rainfall in monsoon | Increasing rainfall in pre-monsoon and monsoon |
Terai | 300 mm to 2700 mm | Over 80% of rainfall in monsoon | Winter rainfall influenced by westerly winds |
Seasonal weather breakdown across the 3 regions
Region | Winter (Dec-Feb) | Pre-Monsoon (Mar-May) | Monsoon (Jun-Sep) | Post-Monsoon (Oct-Nov) |
Himalayan | Snowfall, freezing temperatures | Moderate, dry | Heavy rainfall (80% of total) | Dry, cooler conditions |
Mid-Hills | Cold, dry, occasional frost, fog | Increasing humidity, cloud formation | Heavy rainfall, affecting agriculture | Cooler, dry, some fog |
Terai | Fog, cold waves, cool temperatures | Increasing humidity, rising temperatures | Hot, humid, heavy rainfall | Cooler, slight humidity drop |
Temperature fluctuation and fog across the 3 regions
Region | Temperature Fluctuation | Fog Frequency/Impact |
Himalayan | Extreme fluctuations, particularly at higher altitudes | High humidity, especially in areas like Sagarmatha National Park |
Mid-Hills | Significant diurnal variations, especially in winter | Frequent in valleys, less intense than in Terai |
Terai | Moderate daily fluctuations | Dense fog, especially from November to February, reduces visibility (24-56 foggy days/year) |
References
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