The breezes at this time of year are very pleasant. And the blackbirds and song thrushes are singing all around and it is beautiful. I enjoy having my window open or sitting outside, and being absorbed in it all, lifts up my heart.
The air kasina is great to practise at this time of year, in the Northen hemisphere at least. We have lots of breezes at the moment. Air kasina is basically breath meditation, but there's a component to it which isn't often taught. Which is to focus on the sensation and feeling of the air element as it touches the skin, and notice how that affects the mind. Apparently in ancient times a monk wanting to learn the air kasina would find a cave high in a mountain where there was a breeze and practise there. In modern times, one can practise this in any location with a plug in fan (-:
The fresh air can feel invigorating, and this feeling of invigoration is a breath nimitta. A tactile nimitta, some people get a visual nimitta, but for me the nimitta is always a tactile feeling. In Pali, nimitta means sign. And in this context it is the sign of the air element in the mind; or the effect that the air element has on the mind. It is a mind-generated phenomena, an internal feeling created in response to the air element.
If you stay centred with the nimitta it grows stronger and will expand and fill the whole body, which feels very pleasant and healing. One then keeps intending to stay with it, sustain it, soak the entire body with the tranquility and happiness. This can be challenging to do at first, but it gains momentum over the long term. With consistent practise the nimitta and the feeling of joy and pleasure grows, snowballs, and becomes more effortless and automatic. This is how the mind works, how we create sankharas. Samhadi begets more samhadi, i.e. what we practise grows stronger and becomes a habit, which then carries a momentum and energy of its own that continues and grows deeper.
After many hours of practise, one will be able to bring the air nimitta up at will, without needing a breeze. One can just incline the mind towards it and it will appear. Even the slightest zephyr of air movement in a room will bring it up. Sometimes one can go into absorption just watching the air blowing through the leaves of the trees and plants, or from the ripples it makes on the surface of water. It feels like magic, but it is just how the mind works. The same thing can happen when meditating on any other element, a colour, or on love. One will start to notice it more and more in the world around them and find this will bring up the samhadi associated with it.
A teacher told me that for those brief moments when people take a break from being in a stuffy room and stand outside and enjoy the feeling of the breeze on their faces. For those brief moments those people have been practising breath meditation. He added that when it comes to samhadi, the Buddha says, use the low-hanging fruit. Find that which comes natural and then make it into something supernatural (-: