From Discover Zen: A Practical Guide to Personal Serenity by David Fontana (p. 42, "Zen and Nature"):

As the practice of Zen meditation progresses, so the meditator gains more control, not only over the mind but also over the body. Thus he or she remains relaxed and at peace during long periods of sitting, and becomes immune to many of the rigours of climate encountered while practising outside. The less we feel in conflict with the elements and the less we strive compulsively to change things so that they accord with our own preferences, the more we can live at peace with the world.

^z - 2009-03-13