Salat al-'Asr can sometimes be prayed during midday after Salat al-Zuhr because they share a common time period. The specific times are noon for Zuhr and late afternoon for 'Asr, but there is also an overlapping common time. It is permissible but better to delay 'Asr until the late afternoon time if possible. Similarly, Zuhr can be prayed at the end of its time period even if noon has finished. The intention and specific/common time frames are what matter rather than the common names for the prayers. This principle also applies to Maghrib and 'Isha prayers.