Spiti by road: what the altitude does to your plans
Acclimatisation days are not padding. How to sequence Shimla, Kaza and Chandratal so the high passes do not end your trip early.
Go in via Shimla, come out via Manali
Both roads reach Kaza. They are not equivalent. The Shimla side climbs gradually over three days — Narkanda, Sangla, Kalpa, Nako — and by the time you reach Kaza at roughly 3,800 m your body has had time to catch up. The Manali side crosses Kunzum La at 4,590 m within a single day of leaving 2,000 m.
Driving in the easy direction is the single biggest thing you can do to avoid spending your trip with a headache in a guesthouse.
Two nights below 3,500 m before you sleep high
Altitude sickness is not about fitness and it does not care how many treks you have done. The rule that works is simple: gain height during the day, sleep low, and give yourself two nights somewhere around 2,700 to 3,200 m before your first night above 3,500 m. Kalpa and Nako are both well placed for exactly this.
If you get a headache that paracetamol does not touch, or you cannot sleep and cannot catch your breath lying down, the answer is to descend. It is a three-hour drive down, not an evacuation, and everyone at your guesthouse has seen it before.
Kunzum La and Chandratal open late
Chandratal is reached over Kunzum La, and the pass is typically closed by snow until sometime in late May or June, then closes again around October. The exact dates move every year and are decided by the BRO, not by a calendar.
If Chandratal is the reason for your trip, go between mid-June and late September and build a spare day in. The camps beside the lake are seasonal, unheated and a genuinely cold night at 4,250 m.
Fuel, cash and phone signal
The petrol pump at Kaza is the only reliable one between Reckong Peo and Manali — roughly 200 km of mountain road on either side. Fill up whether or not you think you need to.
ATMs in Kaza exist and regularly do not work. Bring more cash than feels sensible. Only BSNL and Jio hold signal with any consistency, and in Pin Valley almost nothing does.
