as welcome as flowers in May 极受欢迎的；极合时宜的；盼望已久的

【例句】
The guest is as welcome as flowers in May.
这位客人是非常受欢迎的。

We called on my parents-in-law completely unannounced and they made us as welcome as the flowers in May.
我们根本没有通知就去拜访我的岳父母，结果他们也非常欢迎我们去。