At Jonas' first session with the Giver, in Chapter 11, he receives his first memory, which is of snow and a sled. He receives several other memories, as well: sunshine and a sunburn. There is particular significance in each of the Giver's choices.
First of all, he gives Jonas the sled and snow so that they can both understand the Giver's conversational references. However, he chooses to give a memory that is solely pleasant, not unpleasant. The same is true for the memory of sunshine that he next gives to Jonas.
The final memory he gives to Jonas to that day is one of the first true discomforts Jonas has ever felt: sunburn. Jonas, after this activity, declares that he truly understands pain after that experience. The Giver is unable to respond, knowing how much more pain Jonas will have to receive and how this pain destroyed the previous receiver. It is a foreshadowing of events to follow in the novel.