A new study finds allergy season has been getting longer in more than 170 US cities by an average of more than two weeks.

New data from climate central found that the time between the first day of freezing temperatures in the spring and last freeze in the fall has been getting longer since 1970. This gives plants more than two weeks on average to grow, flower, and release pollen. And, in 31 cities, allergy season grew by at least a month since 1970.

Reno, Nevada saw one of the largest increases in allergy season in the country. By 99 days allergy season grew the most in the Western US, followed by the Southeast, Northeast, Southern, and Central US regions.

The researchers suggest these climate changes will have a big impact on people with seasonal allergies and asthma, so talk to your doctors about the best way to manage your symptoms.