Traditionally November - February is our quieter months. It typically begins to pick up sometime in March or April when the weather is warm again. The busiest months here are between June - August.
Then again, a lot of long term hosts (for example @Robin4 , @Helen3) may find that they continue to get bookings despite the decreased demand during the slower months. This is because they have worked up a good reputation, and their listings are extremely competitive. This is why you may hear them saying that they get more and more bookings year over year. I can believe them, because with the current review system this is more or less what happens over time if you continue to rack up good reviews.