April to mid-May: At this time, the snow starts to melt. A number of roads are opened too like road from Kaza to Losar. However, road from Kunzum Pass towards Manali open only in the June month. This is the time when reaching Spiti is feasible and a number of adventure enthusiasts make their plans regarding tour to Spiti. This is an ideal time to admire snow-clad mountains and play in the snow. If you do not really mind low tourist count, can stay amid basic facilities and do not mind certain road blockages, you can travel at during these months.
Mid – May to mid – July: This is the real peak season in Spiti when the valley welcome hordes of tourists who wish to get respite from city heat. Most of the road links by the mid-June get opened and thus sightseeing in and around Spiti is possible. All the hotel also now offer complete facilities. A visit to Chandra tal can also be made. Due to the melting of the snow, you might have to drive on water crossings, thus try to arrive at your destination in the afternoon.
Mid – July to August: These are the monsoon months when monsoon is in full swing in Kinnaur and it is better to avoid this time as the area is prone to landslides. However, Spiti valley itself remains fine at this time, so if you make plans do not forget to buy cartons of apple as they grow the best at this time.
September to mid-October: The autumn season make Spiti absolutely colorful with lush green trees, orange leaves, aqua clean waters and white snow in the background, making the valley, a beauty. The mornings and evenings are quite cold with temperatures going to 2-3 degree Celsius while the days are pleasant. Do not forget to pack woolens. If you are a snow-lover, this might not be an ideal time for you. Try to confirm the weather conditions before making plans as sometimes Kunzum pass starts getting snow as early as September.
November to March: These are winter months in Spiti filled with extreme weather conditions, lack of basic necessities like electricity, several road blockages, water freezing in taps, and almost no hotels offering accommodation. A number of road links at this time on both the routes are closed. If you still make plans, be sure of you mental and physical fitness as there can delays and a lot of risks.