It's about the same as it was when we went for a run together the other day .
この場合、次のような言い方ができますよ。
A: Do you know how cold it is outside today?
「今日外どのくらい寒い?」
B: It's about the same as it was when we went for a run together the other day.
「この前一緒にランニングした時と同じくらい」
to go for a run で「ランニングする」
ご参考まで!