《伤寒论·伤寒例》
所谓时行之气，是指时令的反常气候，如春季天气应该温暖却反而很冷，夏季天气应该炎热却反而很凉爽，秋季天气应该凉爽却反而酷热，冬季天气应该寒冷却反而温暖异常。
凡时行者，春时应暖，而复大寒；夏时应大热，而反大凉；秋时应凉，而反大热；冬时应寒，而反大温。
The so-called current qi refers to the abnormal climate of the season, such as the weather in spring should be warm but it is cold, the weather in summer should be hot but it is cool, the weather in autumn should be cool but it is hot, and the weather in winter should be cold but it is abnormally warm.