This is question I am often asked and I think it comes down to personal preference.
I believe there are merits to both
Practicing yoga outside….
I love to practice and teach yoga outside as I feel much closer to the elements, especially air and water. One of my classes is on the quayside at Dell Quay and the water is constantly flowing in and out of Chichester harbour, it allows me to presence myself more deeply. You will feel really supported by the earth and your practice will be heightened by being able to feel, smell and see nature all around you.
As a teacher I love to cue ‘raise your hands up to the sky’ and ‘flow like water’ and be able to link a movement or pose to what we can see. Boat pose is also a wonderful pose to practice by the harbour where there are boats anchored close by.
In one of my classes one of my students reflected that she had focused her drishti (her gaze) on a swan, which to me was magical. You wouldn’t get that from my yoga studio!
Practicing outside may enable you to be less distracted, there will be more visionary delights outside to feast your eyes on, which might help you create a deeper connection to your body and breath.
Often outside practice is at a park or a beach and likely to be on uneven ground, which could be more challenging for the balancing poses.
Practicing yoga inside
One of the benefits of practicing inside is that you can set up your perfect space, light candles, support yourself with props, diffuse essential oils. Creating an environment which is so personal to you and what you need from the practice.
You will be protected from adverse weather conditions and also have a consistent temperature to practice in. You will be less exposed to air borne allergens, so if you suffer from hay fever or are sensitive to heat or cold this could be more suitable for you.
As a teacher I love to hear collective ujjayi breathing, when all my students feel in harmony with one another as their breath is audible and filling the space. It brings us closer and we feel more supported by each other.
Specific styles of yoga can suit the inside space more – yin yoga is perfect inside where you might just want to drift off to sleep during your savasana.
Should yoga be done inside or outside? I really think really comes down to personal preference and what you need from your yoga practice on any given day. Similar to how your yoga poses are different every time you practice so are your needs and what is going to give you maximum benefit from your practice.