When to use けど vs もっとも?

Question

Is there any nuance between these? From looking up the definitions, they seem similar in meaning (but, although).

Here's a sentence I found that uses both:

もっとも今年の夏は、どこも暑いらしいけど。

Answer 1

An English equivalent of もっとも would be something like "That being said, it should be noted that ～". もっとも is a stilted expression, and it's not common in speech. Small children almost never use it!

Besides, もっとも is used exclusively for adding some precondition, exception, limitation and such. To say very verbosely, もっとも gives off a nuance like "My previous statement is basically true, but should be interpreted taking the following into consideration; ...".

• ✅ 悪いですけど、来週のパーティーには行けません。
  I'm afraid to say this, but I cannot go to the party next week.
• ❌ 悪いです、もっとも明日のパーティーには行けません。
• ✅ 今日は雨が降っています。けど、明日は晴れるといいですね。
  It's raining today. But I hope it'll be sunny tomorrow.
• ❌ 今日は雨が降っています。もっとも、明日は晴れるといいですね。

Answer 2

I don't know where you got the idea that もっとも means "but/although", but its meaning is quite distinct from けど.

The dictionary give two entries for もっとも, one is 最{もっと}も, meaning "most", "to the deepest degree", and is a synonym for 一番. The other entry is 尤{もっと}も, which has the meaning of "certainly", "completely", and is synonym for 当然, 全然, 決して.

Your sentence uses the second meaning(尤{もっと}も), and means this:

もっとも今年の夏は、どこも暑いらしいけど。
Certainly this year's summer seems hot everywhere.

The final けど does not carry any actual meaning here, and is used more like a filler to soften one's tone. For example, if you want to go to the washroom, you could say:

トイレに行きたいんですけど。
I'd like to go to the washroom.

It's better to leave the けど untranslated, as it doesn't really carry the meaning of contrasting two sentences here, or in your example sentence above. It's more like a tone-softener.