وَتَعْجِيلُ الْعَصْرِ وَالْعِشَاءِ فِي يَوْمِ الْغَيْمِ، وَتَأْخِيرُ الْفَجْرِ وَالظُّهْرِ وَالْمَغْرِبِ وَالْوِتْرِ فِيهِ
On a cloudy day the text recommends earlier Asr and Isha, and later Fajr, Zuhr, Maghrib and Witr. The purpose is precaution when sky signs are uncertain.