平时 (píng shí) is a time noun often used as an adverb meaning 'ordinarily, in normal times' — it describes how things usually are, as opposed to a special or exceptional day. Unlike 平常 (which is also an adjective meaning 'ordinary') and 平日 (which specifically means weekdays or non-holiday days), 平时 has a broader sense of 'normal/peacetime'. 通常 (tōng cháng) is a more formal and general adverb for 'usually, normally'.