Gradually; little by little. Indicates slow, steady change or progression over time (similar to 'gradually' or 'by degrees').
寒さは徐々に和らいできた。
The cold has gradually eased.
状況は徐々に改善しているので、もう少し様子を見ましょう。
The situation is gradually improving, so let's watch it a little longer.
彼の態度は徐々に変わっていった。
His attitude changed little by little.
新しい政策は徐々に浸透していくだろう。
The new policy will gradually take hold.