Hā-sî-kan (夏時間, Eng-gí: summer time), joa̍h-thiⁿ sî-kan, ia̍h hā-lēng sî-kan (夏令時間), mā hō chò ji̍t-thâu-kng khiām-iok sî-kan (日頭光儉約時間, Eng-gí: daylight saving time), sī tī Ji̍t-thâu khah chá chhut--lâi hit kúi goe̍h kā chāi-tē ê piau-chún-sî (tang-sî-kan) tiâu chìn-chêng, pí-lūn kóng kā sî-kè tiâu kín 1 tiám-chéng. Án-ne, ē-tit khah tah-té lī-iōng ji̍t-thâu-kng, khiām-iok lêng-goân.

  leh si̍t-hêng hā-sî-kan
  bat si̍t-hêng hā-sî-kan
  m̄-bat si̍t-hêng hā-sî-kan

Tâi-oân tī 1945 nî kàu 1961 nî, 1974 nî, 1975 nî lóng ū si̍t-hêng hā-sî-kan.