KATHMANDU: Persistent fog across the Terai and the possibility of light snowfall in Nepal’s high mountains are likely to affect tourism, transport, and aviation over the next few days, the Department of Hydrology and Meteorology (DHM) has warned.

Under the influence of westerly winds, Koshi, Gandaki, Karnali and Sudurpaschim provinces may see light rain or snowfall at higher elevations, while dense morning and night-time fog continues to reduce visibility in the Terai. Conditions are expected to gradually improve from January 7, though fog may linger in lowland areas.

Mountain and hill regions

There is a possibility of light rain or snowfall at one or two locations in high hilly and mountainous areas of Koshi, Gandaki, Karnali, and Sudurpaschim provinces through January 6, with improving conditions expected by January 7.

The DHM has warned that these conditions may affect trekking routes, mountain tourism, aviation, and road connectivity, especially in high-altitude destinations.

Terai fog and cold conditions

Dense fog and mist are expected to prevail across most parts of the Terai, particularly during mornings and nights, potentially disrupting road transport, domestic flights, agriculture, and daily life.

DHM data recorded very low visibility in several Terai locations on Monday morning:

• Nepalgunj: 50 metres (dense fog)
• Bhairahawa: 300 metres
• Dhangadhi: 1,500 metres
• Biratnagar, Janakpur, Chandragadhi: Around 2,500 metres

(Visibility below 1 km is classified as fog, while 1–5 km is considered mist.)

The department said fog conditions are likely to gradually improve after noon, with Sudurpaschim Terai expected to clear slightly earlier than other regions.

Three-Day Outlook (Jan 5–7)

January 5–6:

• Fog/mist across most Terai districts
• Partly cloudy hills and mountains
• Light rain/snowfall possible in high-altitude regions

January 7:

• Gradual improvement nationwide
• Mainly fair weather in hills and mountains
• Morning fog likely to persist in the Terai

Weather Advisory 

• High mountains: Light rain/snowfall possible in parts of Koshi, Gandaki, Karnali and Sudurpaschim through January 6. Trekkers and guides should check trail and pass conditions.
• Terai region: Dense fog and mist during mornings and nights may disrupt road travel and domestic flights. Expect low visibility, especially in western Terai airports.
• Aviation & transport: Potential delays on domestic flights and highways; travellers are advised to allow extra time.
• Health caution: Cold, foggy conditions may affect the elderly and children; warm clothing and hydration are advised.