JOINING PRAYERS BECAUSE OF RAIN
f15.14 It is permissible for a nontraveller to pray the noon prayer (zuhr) and the midafternoon prayer (`asr) at the time of the noon prayer (N: or the Friday prayer (jumu`a) and midafternoon prayer at the time of the Friday prayer), and to similarly pray the sunset prayer (maghrib) and nightfall prayer (`isha) at the time of the sunset prayer if:
(a) it is raining hard enough to wet one's clothing (O: and like rain in this is melted snow or hail);
(b) one is praying with a group in a mosque (O: or other place of prayer);
(c) the mosque is far (O: from one's door, i.e. far by common acknowledgement (def: f4.5));
(d) it is raining when the first prayer begins, when it ends, and when the second prayer begins;
(e) and conditions f15.10 (b,c,d) exist.f15.15 (A: If one arrives during the second of two prayers joined because of rain and does not finish one's own first prayer before the group finishes their second, then one is no longer entitled to join one's prayers for rain. It is a necessary condition that one pray at least part of the second prayer with them though one may hurry through one's own first prayer alone to catch up with and join them during their second.)
f15.16 If the rain stops after one finishes the two prayers or during the second one, both prayers are and remain valid.
f15.17 It is not permissible to join two prayers in the time of the second of them because of rain.
f15.18 (n: In the Shafi`i school, there are no valid reasons other than travel or rain for joining prayers, though others exist in the Hanbali school, as discussed in what follows.)
(`Abd al-Rahman Jaziri:) The hanbalis hold that the above mentioned joining between the noon prayer (zuhr) and midafternoon prayer (`asr), or between the sunset prayer (maghrib) and nightfall prayer (`isha) is permissible, whether in the time of the first prayer of each of these two pairs, or in the time of the second prayer of each of them, though it is superior not to join them.
It is a necessary condition for the permissibility of joining them that the person praying be:(1) a traveller on a trip in which shortening prayers is permissible;
(2) a sick person for whom not to join prayers would pose a hardship;
(3) a woman who is nursing an infant, or who has chronic vaginal discharge (dis: e13.6), since she is permitted to join prayers to obviate the hardship of purification for every single prayer;
(4) someone with an excuse similar to the woman with chronic discharge, such as a person unable to prevent intermittent drops of urine coming from him (e 13.7);
(5) or someone who fears for himself, his property, or his reputation, or who fears harm in earning his living if he does not join prayers; the latter giving leeway to workers for whom it is impossible to leave their work. (al-Fiqh `ala al-madhahib al-arba`a (y66), 1.487)