There are many varieties of hares, so it depends.
Arctic Hare- Tundra, Boreal Forest
Desert hare- dry deserts
You can also have hares in grassland biomes (plains/savannah/scrub.) The only one where they might no be as common is in a rainforest. If you think about the adaptations of a hare, they work best in places where they can outrun predators or blend into the surroundings. Because hares don't climb trees or swim, you could make the assumption that they don't live in heavily treed areas or aquatic ecosystems.
