What does どうやら mean?

Question

明日はどうやら雨らしいよ。
It looks like it's going to rain tomorrow.

The English definition given (in Core 6k) is "seems, looks like", but in this sentence and other example sentences I've seen, it's generally paired with words that have similar English definitions such as らしい、よう、～そう. What does どうやら add to the sentence that isn't already covered by these other words? If I changed the example sentence above to 明日は雨らしいよ。, how would the meaning change?

Answer 1

As a Japanese-speaker, my first reaction upon reading your question was like "Since when is どうやら a verb!?"

「どうやら」 is an adverb （[副詞]{ふくし}） in Japanese even though your source appears to give verbs (to seem, to look like) as its definitions. And because 「どうやら」 is an adverb, it is perfectly natural that it is used together with the auxiliary verb 「らしい」. There is no redundancy there.

「どうやら」 means "not certainly but probably", "in some way", etc.

「らしい」 means "to look like", "to seem like", etc.

These two words are often used together to express an inference based on grounds.

If you said 「[明日]{あす}は[雨]{あめ}らしいよ。」, it would surely be understood but it could sound kind of curt depending on the situation. It would sound like you said it using the fewest words possible. I admit that adding 「どうやら」 will not change the meaning of the sentence much, but it will sound "more normal" or more like human conversation.

Answer 2

「明日は雨らしいよ」- "I heard it's gonna rain" The speaker is unobjectively stating that he has received information from a 3rd party source indicating that it is going to rain.

「明日はどうやら雨らしいよ」- "It seems that it's going to rain" The speaker is objectively stating that he has received information from a 3rd party source indicating that it is going to rain and not implying whether he believes that it will rain himself or not.

「どうやら」is a way for the speaker to emphasize his objectivity or possibly doubt.

See the second definition from the 大辞林 dictionary here: http://www.weblio.jp/content/%E3%81%A9%E3%81%86%E3%82%84%E3%82%89