Sissu in December is cold and increasingly snowy — expect daytime highs of roughly 0–8°C, nights below freezing, and building snow as the month goes on. The Atal Tunnel keeps the road open, but fresh snowfall can cause clearing delays, so always check before you travel.
Quick answer: what is Sissu like in December?
Sissu sits on the floor of the Lahaul valley at roughly 3,100 m (about 10,170 ft), just north of the Atal Tunnel. In December that altitude means genuinely cold days, sub-zero nights and snow that builds steadily as the month goes on. Early December often carries leftover snow from late-November storms, while mid-to-late December is when fresh snowfall becomes likely and the valley turns properly white.
The good news is access: the Atal Tunnel keeps the Manali–Sissu road open right through winter, so — unlike the old Rohtang route — Sissu no longer gets cut off when the snow arrives. December is a great month for snow with the fewest tourist restrictions, but it rewards travellers who come prepared and stay flexible. If snow is the whole reason you’re coming, see our wider best time to visit Sissu guide for how December compares to January and February.
Weather & temperature in December
December weather in Sissu is cold and changeable. Clear, sunny days are common — and the high-altitude sun can feel surprisingly strong — but temperatures stay low. Daytime highs typically sit in the ~0–8°C range, and the moment the sun drops behind the peaks the temperature falls quickly. Nights are reliably below freezing, and during a cold spell or after fresh snow they can drop to around –10 to –15°C.
The single most important thing to understand about December here is how fast conditions can change. A bright, calm morning can turn into a snow shower within hours when a western disturbance moves through. Plan your days around daylight, keep an eye on the sky, and treat any temperature figures as a guide rather than a forecast — they vary year to year.
| Part of December | Typical conditions | Snow & roads |
|---|---|---|
| Early December | Cold, often sunny days; sub-zero nights | Leftover snow likely; roads usually clear but cold |
| Mid December | Colder; first proper snow spells common | Fresh snowfall builds; brief clearing delays possible |
| Late December | Coldest part of the month; deep cold at night | Snow well established; waterfall starts to freeze |
Will it snow in Sissu in December?
Most likely, yes — especially from the middle of the month onward. December sits right at the start of Lahaul’s heavy winter season. Snowfall in Sissu isn’t continuous or perfectly predictable; it comes in spells driven by western disturbances. But the trend through December is clear: the valley gets whiter and the snow on the ground deepens as the weeks pass.
Early December can be a mix of leftover snow and clear ground, so if a fully white valley is essential to your trip, mid-to-late December is the safer bet. This is also when the Sissu Waterfall (Palden Lhamo Dhar) begins to freeze into ice — it usually reaches its dramatic frozen column a little later in deep winter, but late December often gives you the first impressive stages. Snow totals vary hugely year to year, so we can’t promise a specific depth — message us and we’ll tell you honestly what’s on the ground right now.
Is the road to Sissu open in December?
Yes — for most of December the road is open, and this is the big change the Atal Tunnel brought. Because the tunnel runs under the mountain instead of over the old, snow-bound Rohtang Pass, the Manali–Sissu route now stays open through winter rather than closing for months. That is exactly why a December trip to Sissu is realistic at all.
The honest caveat is heavy snow. After a significant snowfall, authorities carry out snow-clearing on the highway and around the tunnel portals, which can mean temporary closures or delays until the road is reopened. These are usually short, but they’re unpredictable, so you should never travel on a tight, fixed schedule in December — always build in buffer days.
One more thing to plan around: the Lahaul valley usually sees a winter tourism break that begins later — around 20 January — so most of December falls comfortably before it. Still, dates and rules shift from year to year, so confirm the current situation before booking. For the live picture, check whether Sissu is open right now and read our how to reach Sissu guide for the route itself.
Things to do in December
December is the start of Sissu’s snow season, and the quiet, white valley is a large part of the appeal. With far fewer visitors than summer, you get the snowscapes largely to yourself. Popular things to do include:
- Snow play & photography: a fresh-snow morning in the valley, framed by white peaks, is the classic December experience.
- Sissu Waterfall: watch it begin to freeze — even partly frozen, it’s a striking sight in late December.
- Sissu Lake & the valley floor: calm, scenic walks on clear days; see our Sissu Lake page for more.
- Atal Tunnel drive: the journey itself, through the tunnel into a snowy valley, is memorable.
- Slow, cosy days: with short daylight hours and deep cold after dark, December is also a trip for warm rooms, hot food and views from indoors.
For the full year-round list, see our things to do in Sissu guide. In December, plan outdoor activity for the daylight hours and keep evenings relaxed.
What to pack for December
December in Sissu is a serious cold-weather trip, and being properly kitted out is the difference between enjoying the snow and being miserable in it. Pack:
- Heavy woollens & insulation: a warm insulated jacket, thermals, fleece layers, woollen cap, gloves and thick socks.
- Snow-appropriate footwear: waterproof boots with good grip — ordinary shoes are slippery and cold on packed snow.
- Sunscreen & sunglasses: snow glare and high-altitude sun are intense even on cold days, so protect your skin and eyes.
- Power bank & chargers: batteries drain fast in the cold, so keep phones topped up.
- Personal medication & a basic first-aid kit, plus any altitude-related precautions you usually take.
- Buffer days in your itinerary, in case snow-clearing delays the road.
For a complete checklist, see our dedicated what to pack for Sissu guide. Our rooms come with 24×7 hot water, heaters and warm bedding, which makes the December cold far more comfortable once you’re back indoors.
Safety tips for a December trip
A December trip to Sissu is genuinely rewarding, but the cold and snow demand respect. A few simple rules keep it safe:
- Drive in daylight only. Roads can be icy, light is short, and conditions are easier to read by day. Avoid being on the highway after dark.
- Carry snow chains, or hire a local driver. Drivers experienced with snow and the tunnel route are far safer than self-driving on packed snow if you’re not used to it.
- Check the status before and during your trip. Snowfall and clearing closures change fast — confirm with us on WhatsApp before setting off.
- Keep buffer days. Don’t plan a tight schedule around a fixed onward flight or train; build slack in case the road is briefly closed.
- Dress for the cold and stay dry. Wet clothing in sub-zero temperatures is a real risk — layer up and keep extremities covered.
- Go easy on day one. At 3,100 m, take the altitude gently, stay hydrated, and rest if you feel unwell.
Frequently Asked Questions
Does it snow in Sissu in December?
Yes, most likely — especially from the middle of the month. Snowfall comes in spells rather than continuously, but the trend through December is steadily more snow, and the valley is usually white by mid-to-late December. Early December can be a mix of leftover snow and clear ground, so for a fully white valley, mid-to-late December is the safer bet.
How cold is Sissu in December?
Cold. Daytime highs are typically around 0–8°C, often under clear sun, while nights are reliably below freezing. During cold spells or after fresh snow, nights can drop to roughly –10 to –15°C. Treat these as a guide — they vary year to year — and pack for serious cold.
Is the road to Sissu open in December?
Yes, for most of December the Manali–Sissu road stays open thanks to the Atal Tunnel, which runs under the mountain instead of over the old Rohtang route. The one caveat is heavy snowfall, which can cause temporary snow-clearing closures or delays, so always check the live status before you travel and keep buffer days in your plan.
Is December a good time to visit Sissu?
If you want snow and a quiet valley, yes. December offers building snow, the start of the frozen waterfall, far fewer crowds than summer, and — importantly — it falls before the valley’s later winter tourism break (which usually begins around 20 January). It suits travellers who enjoy the cold and come properly prepared.
Is the Atal Tunnel open in December?
Yes. The Atal Tunnel is the reason Sissu is reachable in winter at all, and it generally stays open through December for transit. After heavy snowfall there can be temporary traffic control or short closures around the portals for clearing, but these are usually resolved quickly. Confirm the current status with us before setting out.
What should I pack for December?
Serious cold-weather kit: a heavy insulated jacket, thermals, fleece layers, woollen cap, gloves and thick socks, plus waterproof snow boots with grip. Add strong sunscreen and sunglasses for snow glare, a power bank (batteries drain in the cold), any personal medication, and buffer days in your itinerary. See our full what to pack for Sissu guide for the complete list.
Planning a December snow trip to Sissu?
Message us on WhatsApp for today's road and snow status. Warm rooms, 24x7 hot water and heaters at Hotel Lake Side Inn.
