This is the 13036th most frequent Russian word.
майские
"May holidays" or "things related to May."
In this sentence, 'майские' refers to the holidays in May, commonly celebrated in Russia, highlighting its substantive use relating to these specific holidays.
Мы планируем провести майские праздники на природе.
We plan to spend the May holidays in nature.
Here, 'майские' describes the flowers characteristic of May. It is an adjective modifying 'цветы' (flowers), showing its descriptive role.
Майские цветы начинают распускаться, украшая город.
May flowers begin to bloom, decorating the city.
In this case, 'майские' is used to specify a characteristic phenomenon of May—the May rains, functioning as an adjective modifying 'дожди' (rains).