The Har Ki Dun Trek is often grouped into Easy / Moderate categories; however, it is an enjoyable but deceptively difficult trek that mixes easy uphill with the rigours of trekking in the High Himalayas. The trek does not have any technical vertical sections, however, it does have a significant amount of endurance over approximately 50 kms of undulating terrain and 11,600 feet of elevation gain. As for the seasons on this trek, the difficulty of the Har Ki Dun will change dramatically; in the spring months, the trek is a relatively easy, sunny, and well-maintained path through a beautiful primeval jungle; however, in the winter months, it is a true test of one's ability and perseverance, as snow can be waist-deep and temperatures can be below freezing. Therefore, the difficulty is more in relation to the physical labour required to sustain an individual over several days, while adjusting to the thinness of the oxygen supply available, and dealing with the erratic weather patterns associated with the Tons Valley region.

To accurately assess the level of difficulty on the Har Ki Dun Trek, you must go beyond using broad beginner classifications and instead focus on all the components unique to this section of the Himalayas. The difficulty of this trek is like a multi-dimensional crossword puzzle because there are many variables that come into play (e.g., geology, oxygen, and mental). Therefore, to properly assess the true level of difficulty associated with trekking through the Tons Valley, you must break these variables down into their component parts so that you can gain a clear understanding of their cumulative influences.

• The Trail: The trail offers a variety of landscapes that include ancient forests, large open meadows, and riverbank areas. You will be trekking through forests with dense pine and oak trees, through the large C-shaped valley that is surrounded by mountains. The major geographical point of interest is the Supin River where you will be crossing wooden bridges to get to the other side.
• The Challenge: Although the incline of the trail is not extremely steep, you will find that there are few areas that are level. You will encounter loose rocks, wet mud (after rain), and uneven terrain with boulders as you approach the glacier called Jaundhar Glacier. The last part of the trek to Har Ki Dun includes a lot of switchbacks that can create difficulty for your knees.
• Honest Take: Overall, this is the most well-defined trail in Uttarakhand. However, even though you will be able to see and visualize the meadows, the actual ground conditions vary constantly and can vary even within a day's time due to weather related events.

• The Stats: You depart from Sankri (1,950 m / 6,400 ft) before reaching a maximum of around (3,566 m / 11,600 ft) at the Har Ki Dun campsite.
• The Challenge: You have trekked over 1,600 m of elevation gain. While 11,600 ft falls below the extreme altitude line (12,500+ ft) it is still an altitude that can cause Acute Mountain Sickness (AMS). Your body will respond to this elevation by experiencing a decrease in oxygen saturation which will manifest itself as a shortness of breath and an increase in your heart rate as you trek to the top.
• Honest Take: There is a general agreement among most individuals who are reasonably fit that this elevation is the sweet spot; it is high enough to be exposed to the high mountain air but not sufficiently extreme to encounter significant elevation related sickness from a rapid ascent from Osla to the Valley. However, if you take your time on the ascent from Osla to the valley, you may be affected by the pounding of an elevation headache as well.

• The Weather: The Valley has its own specific micro-climate due to its valley location. The weather during the spring/summer months (10°C to 20°C) is comfortable for trekking, but in winter the temperature can drop down to -10°C.
• The Challenge: The biggest obstacle to be prepared is the diurnal fluctuation of temperature. You may find yourself in the middle of your trekking day at 2:00 PM wearing a T-shirt and then at 6:00 PM putting on an ultra-heavy down jacket to keep warm.
• Honest Take: There is also the possibility of sudden afternoon thunderstorms during the pre-monsoon months, which can quickly result in drops of the temperature of 10 °C above the valley to below freezing.

• The Stats: Journey of 7-day trek taking approximately 44 - 55 km (return).
• The Challenge: You are in the Govind wildlife sanctuary with no source of cell phone and limited electric power after leaving Sankri. The most challenging part isn't physically enduring the trek; it is experiencing disconnection from society, such as sleeping in tents, using dry toilets, and being called separated from a hospital or motor road by several days.
• Honest Take: After trekking 30 km over two days begins to disengage the mind as well as body. This trek tests both mental determination and physical endurance/strength.

While Har Ki Dun is generally considered a beginner’s trek, it can be extremely challenging both physically (through the terrain) and mentally. Difficulty does not stem from technical trekking but rather from the accumulated fatigue of having trekked over 50 km during six days of trekking in an altitude where oxygen levels are lower than those found at sea level. The final portion of this trek represents both a test of one’s will to finish and heart health - requiring you to navigate false flats before reaching the steepest section, where you'll trek 11,600 feet above sea level with limited oxygen. This trek will be possible for those who wish to take it on as a beginner; however, the greatest challenge is simply sustaining the effort for so long as well as doing an 18 km (over a river and through the woods!) roundtrip to Jaundhar Glacier.

Har Ki Dun is very often labelled beginner-friendly, but this label tends to mislead when it comes to the actual experience you are going to have while trekking on the trail.

• Myth: Most first-timers think of beginner-friendly as meaning that the trek is going to be a gradual stroll, something similar to walking through a city park or taking a small hike at a hill station. People have a misconception that the slopes are gentle, you do not have to train physically or develop mountain legs to complete the trek.
• Reality: Har Ki Dun is an endurance trek. Although it does not require any technical trekking (you do not use a rope or ice axe), it does require a significant amount of physical exertion to complete the trek. The distance you will cover in the course of completing Har Ki Dun is approximately 50–54 km, which will take you 5–6 days to trek.
• Distance Trap: While you may trek 10 km on a treadmill, walking 10 km on a fluctuating and uneven trail in the Himalayas while carrying a backpack (7–10 kg) is very different.
• Cumulative Fatigue: On Day 3 of your trek, due to the elevation you will reach (11,700 ft), your body will not fully recover as quickly as it did on Day 1. You will find that small hills that seemed easy to trek upon on Day 1 will be much more difficult to trek upon and feel much heavier to your legs.
• Verdict: The safety and terrain of Har Ki Dun make it an excellent choice for someone who is new to trekking. However, it does require an intermediate level of stamina. If you have trained for at least three weeks before trekking this trail by building up your baseline endurance or cardiovascular fitness, you will be well-prepared to trek Har Ki Dun.

The summit push on the Har Ki Dun trek differs from the Kedarkantha or Chandrashila treks, which feature a singular peak ascent at night. Rather, trekkers will be trekking through a large, enclosed high-altitude alpine basin while on this trek.

• The False Flats: The final approach to Har Ki Dun valley floor, starting at Kalkattiyadhar, can be deceptive for trekkers mentally. As trekkers wind their way through the winding routes leading up to the valley, there are many instances of false flat sections that create an assumption of how far the valley is only to then lead trekkers to believe the valley is a large distance from them.
• The Last 500 mtr: In general, the trails are mild uphills; however, just prior to coming out of the valley approximately 1km (or 0.5 miles) of steep uphill trek at the top (the final 500m) can create a dramatic spike in heart rate due to lack of oxygen and heavy breathing at about 12,000'.
• The Hard Mode: The end of the first half of the trek (Har Ki Dun) is not the end of the trek for many people. People can continue on to the second half of the trek, which is a journey to either Maninda Tal or Jaundhar Glacier. The additional trek to Maninda Tal or Jaundhar Glacier comprises a distance of approximately 5–8km (3.1–5 miles) on the same day. The mode of trek on the glacier's moraine (loose rock and rubble) can be much more difficult and technical than the trails to the valley and can create a challenge for trekkers that extends the overall time for the trek to between 8–10 hours on the last summit day.
• Verdict: The ruling is that the summit involves waiting and using up all the air we have left in our lungs. It's not the vertical trekking challenge that people might think; instead, it's keeping going as long as you can while breathing less and having longer to go.

1. The Beginner Trekker: For new mountain trekkers looking for their first trekking to the higher altitude Himalayas, this is the ideal experience to get you started. It contains all the elements of a great trekking adventure, yet does not impose the same level of risk as many of the larger mountain peaks do. The trek is geared towards beginners who would like to put in a few weeks of training to be rewarded with the stunning views found in the Himalayas.

2. The  History and Culture Enthusiasts: This trek is different from most other treks which are purely nature-based. The Har Ki Dun Trek takes you through parts of India that still contain a living history with people living there today. If this is something that interests you then this trek is for you:

• Experience the Village of Osla and Gangad which are over 2,000 years old.
• See unique wooden temples and architecture dedicated to Lord Shiva (Someshwar).
• Take the Stairway to Heaven and walk in the footsteps of the Pandavas from mythology.

3. The Nature Photographers: This trek is a constantly changing visual feast that people can view and photograph all day long. It is for individuals who are not necessarily interested in just the destination, but would also like to photograph:

• The sun illuminates the peaks of Swargarohini during the Golden Hour.
• The rare wildlife of the Himalayas such as the Himalayan Monal and the Bharal.
• The changing colors of the meadows after a rain shower.

4. The Peace Seeker: This is an ideal trek for those seeking solitude during the shoulder season months (late October or early March). The vast nature of the valley allows for places where you will have only the sound of the Supin River and the wind blowing against the nearby. glacier

1. Kedarkantha vs Har Ki Dun: The main difference is that Kedarkantha is a summit and Har Ki Dun is a valley experience. Kedarkantha is a quick and easy way to get to altitude (it can be done in 4 days with short distances). Har Ki Dun is more of a sustained power marathon; Kedarkantha is a single peak summit while Har Ki Dun is a 7-day experience that immerses you in the largest glacial valley. Har Ki Dun can involve nearly double the distance of Kedarkantha and is much more physically demanding due to the gentler gradients of Har Ki Dun.

2. Brahmatal vs Har Ki Dun: Brahmatal and Har Ki Dun are both approximately the same altitudes, but they each provide different scenery. Both treks offer spectacular views of Mt. Trishul and Nanda Ghunti from the high ridges that surround them, but Brahmatal is perhaps best known for its incredible transitions from forests to meadows, while Har Ki Dun provides excellent views of the Swargarohini massif, which towers over the trek. Brahmatal's treks generally have a steep, short burst of trekking, while Har Ki Dun has a longer, more stable trekking pattern through ancient villages and river valleys.

3. Sandakphu vs Har Ki Dun: The difference between Sandakphu and Har Ki Dun is best represented in their types of treks: Sandakphu Trekking, is an easy-moderate trek along the border between India and Nepal with a series of overnight stays at lodges, while Har Ki Dun Trekking offers a true experience of nature, since you will be staying in tents and travelling on foot on a trail that cannot accommodate vehicles. People who attempt the Sandakphu Trek will enjoy more physical comfort, as well as a far more magnificent view of distant objects, than the Har Ki Dun Trek will provide. 

Verdict: Kedarkantha has the advantage of more quickly gaining an ego boost via its summit, while Sandakphu provides larger lodge-based accommodations and beautiful views of Mount Everest. However, Har Ki Dun has more of a cultural experience and depth of cultural immersion than the other three treks combined. Har Ki Dun provides the experience of true time travel, where you must earn its beauty through distance and stamina—not just a single steep ascent. If you are interested in experiencing a genuine wilderness trekking adventure, then pick Har Ki Dun. Otherwise, if you are pressed for time and enjoy greatest hits views, you should choose the other three options.

To transition from finishing the trek to enjoying every moment spent in the Valley of the Gods demands two primary focal points when determining how you are physically and mentally prepared for the upcoming trek. It is essential that you create a training plan that consists of an Aerobic Engine and Gear that can operate in the Valley of the Gods’ variable microclimates.

Since the Har Ki Dun is an endurance trek, as opposed to a technical trek, you need to focus on how much time you are going to spend on your legs. Ideally, you should be able to comfortably carry out a 6-7 hour long walk over the course of 5 days without coming close to failure.

• Building Your Aerobic Base: Start your aerobic base training at least 4 weeks in advance of your trek. Focus on low-intensity long duration aerobic training with a concentration of 4 days per week (i.e., 5 km runs or brisk walking for at least 60 minutes). You won’t be concerned with speed here, your training is to enable your heart to efficiently pump oxygen into your body in a low oxygen environment.
• Leg Conditioning: Weighted Lunges and Step Ups should be included in your leg conditioning regimen. The descent from Har Ki Dun to Taluka is a toe-crushing 14km. The majority of your quadriceps and calves will be handling eccentric loading, (i.e. downhill braking).
• Backpacking Simulation: For your last two weeks of training, do all of your walking with a 5-7 kg backpack on your back, this prepares your shoulders and lower back to handle the added weight when you are actually carrying your backpack while trekking.

In the Himalayas, the gear is all about thermal regulation, not so much about fashion. The temperatures can swing by 20 degrees during the course of one afternoon. Therefore, your gear will need to be modular.

• The Layering System: Never rely on just one heavy jacket. Instead, you should follow the three layer rule: A moisture-wicking base layer (made of polyester or merino wool), an insulating mid-layer (such as fleece or down), and an outer shell that is both waterproof and windproof. This way you can add or remove layers based on whether the afternoon slump or morning sun dictates.

Footwear is Essential: It is crucial to invest in high-performance waterproof trekking boots which have deep lugs (for grip) and ankle support. The ground in this area consists of a combination of loose rocks, mud, and slippery pine needles. Be sure to break in your boots by walking for 20–30 km at the very least before you arrive at Sankri.