天気だった

The weather was nice., the weather was

→ 天気
phrase Common #3,823
The weather was nice. A natural way to say that the weather was pleasant or fine.
JA: 昨日は最高の天気だったよ。
EN: The weather was perfect yesterday.

昨日は最高の天気だったよ。

The weather was perfect yesterday.

絶好の天気だった。

The weather was absolutely perfect.

素晴らしい天気だった

The weather was wonderful.

— 鏡 (1975)

よい天気だったので私達は一層楽しかった。

Because the weather was nice, we enjoyed ourselves even more.

すばらしい天気だった。

It was beautiful weather.

phrase Rare #37,862
the weather was Describes the weather conditions at a past time; 天気 means “weather,” and だった is the plain past form of “to be.”
JA: ひどい天気だった。
EN: The weather was awful.

ひどい天気だった。

The weather was terrible.

違う日に行ったら違う天気だった。

When I went on a different day, the weather was different.

外に出たら予想外の天気だった。

When I went outside, the weather was not what I expected.

気持ちのよい天気だったが、公園にはほとんど人がいなかった。

The weather was lovely, but there were hardly any people in the park.