悪かったので

because it was bad

→ 悪い
phrase Uncommon #10,166
because it was bad A combination of 悪かった (was bad) and ので (because), used to give a reason. The subject of 悪かった depends on context, such as weather, conditions, or someone's behavior.
JA: 天気が悪かったので、試合は中止になりました。
EN: Because the weather was bad, the game was canceled.

天候が悪かったので私たちはピクニック中止せざるをえなかった

The weather was bad, so we had no choice but to cancel the picnic.

車の調子が悪かったので会社へバスで行かなければならなかった

My car was having trouble, so I had to take the bus to work.

天気が悪かったので彼らは泳げなかった

They couldn't swim because the weather was bad.

気分が悪かったのでその日は家にいました

I felt sick, so I stayed home that day.

天気が悪かったので試合は延期された

The game was postponed because of the bad weather.

彼女は子供が人前でお行儀悪かったのでとても当惑した

She was very embarrassed because her child behaved badly in public.

お腹の調子が悪かったので学校を休みました

I had an upset stomach, so I stayed home from school.