OK, so what do you think of when you think of red? Fire, passion, and love…exactly. Red is a pretty intense color. Possibly the intense color. So when Jonas starts seeing the color red, he's not just seeing the color red. He's seeing passion, fire, and love. That's why it's so fitting that Fiona – the girl Jonas does have feelings of attraction for – has red hair. It's also fitting that at the peak of the novel's emotional intensity – when Jonas is trying to survive and clinging onto desperately to his last bit of hope and courage – we get the color red again, this time in the sled he finds at the top of the snow-covered hill. See how that works out?