Hey Monika, Yes, you can visit Spiti in March but weather will be cold there ( -15 to 5 Degree Celsius ). The Best and most scenic route to reach Spiti Valley is via Manali. You can also do a round trip: Manali->Spiti Valley->Shimla. Best time to visit Spiti is from June -September as road via Manali remains closed in the rest of the months but you can visit via Shimla. Happy travelling!!!!!!!