Non-weather usage of 日和

Question

I'm aware that 日和 can be used with weather conditions to show that it's a good day for something.

今日はピクニック日和ですね。
Today's the perfect day for a picnic.

But can you use it for non-weather related situations? If I wanted to express that a given book is a great book to study Japanese with (it has an interesting story, plus good vocab and furigana for instance) could I say:

その本は日本語の勉強日和です。
That book is perfect for studying Japanese.

goo辞書 lists a possible definition as 「物事の成り行き。雲行き。形勢。」, so I thought maybe so. Or is there a more natural way to express this?

Answer 1

日和 may not always refer to weather, but it always refers to a perfect day for doing something. It's typically used like 雨の日は勉強日和だ ("Rainy days are perfect for studying"), but IMO it's also natural to say テスト前に3連休があるので勉強日和だ (although some may argue this is not a traditional usage). Either way, この本は勉強日和だ makes no sense.

I think the 雲行き/形勢 meaning is applicable almost exclusively in the set expression 日和見 and 日和見主義 today.