In its quest for unilateral sameness, the community has literally lost touch with the beauty of extremes in life. Through Climate Control there are no longer any weather variations; the variations in topography have been flattened out; there is no longer even any distinction of colour. In the attempt to avoid all pain, suffering and even discomfort, the community members have gradually lost the reference points needed to subjectively appreciate contrast and difference.
It is ironic that each night there is a family ritual to talk about each other's feelings as a kind of debriefing from trauma. There is no personal realm of experience left as even this become corporate "property."
When Jonas decides to stop taking pills to repress his sex drive, this is really his first act of revolt against the system. He revindicates both his right to feel and to experience individual choice outside of the sanction of the group.
The Giver imparts the experience of snow to Jonas because he wants to start with a positive experience rather than a negative one, but underneath perhaps he wants him to reappropriate this "difference" which has been lost. It paves the way for Jonas's final choice to flee the community with Gabriel for a life elsewhere, now that he knows that "otherness" is possible.