Hay fever is an allergic reaction to pollen. Tree pollen usually affects people in the spring, grass pollen in June and July, and weed and mould pollens in the autumn. It’s also referred to as seasonal allergic rhinitis and often related to chronic allergic rhinitis that can endure all year round.
Hay fever affects about 1 in 4 people in the UK and is usually worse between late March and September. This is when the weather is more likely to be warmer, windy, humid and when the pollen count is at its highest.