"Indeed, We sent upon them a sarsar (roaring) wind," and the sarsar is the cold [wind] that is intense in its coldness, and it is the westerly wind (al-dabur). "In a day of continuous misfortune," meaning: ominous. "Continuous," it continued with the torment, and that was from Wednesday to [the following] Wednesday.
﴿إِنَّا أَرْسَلْنَا عَلَيْهِمْ رِيحًا صَرْصَرًا﴾ والصرصر: الْبَارِدَة الشَّدِيدَة الْبرد، وَهِي ريح الدَّبور ﴿فِي يَوْمِ نَحْسٍ﴾ أَي: مشئوم ﴿مُّسْتَمِرّ﴾ اسْتمرّ بِالْعَذَابِ، وَكَانَ ذَلِك من يَوْم الْأَرْبَعَاء إِلَى يَوْم الْأَرْبَعَاء.
