Prayer of the Traveler
Islamic Law makes the salah easier for a traveler in two ways:
Qasr: the four rak’ah salah is shortened to two rak’ah.
Jama’: Dhuhr can be combined with Asr, Maghrib can be combined with ‘Isha. Prayers, however, cannot be combined in any other way. Fajr cannot be combined with ‘Isha, Fajr can not be combined with Dhuhr. Asr can not be combined with Maghrib.
Conditions
Qasr is performed when one is traveling. You cannot shorten the prayers unless you have actually left your city limits. There is no time limit as to how long you can shorten the prayers. The majority of scholars allow it for up to four days and nights, though. In case of bad weather, prayers can be combined (but not shortened) in the mosque so worshippers, do not have to come back to the Mosque while the weather is bad.
Method
There are two ways to combine prayers.
First, Dhuhr is prayed on time and Asr is combined with it. This means that Asr is offered before its time in the time for Dhuhr. Similarly, Maghrib is prayed on its time with ‘Isha. ‘Isha is offered early in the time of Maghrib.
Second, Dhuhr is delayed beyond its time and offered with Asr and Maghrib is delayed beyond its time and offered with ‘Isha. In both cases, Asr and ‘Isha are prayed in their times, but Dhuhr and Maghrib are delayed until the time of the following prayer.
Prayers are joined with one Adhan and two Iqamahs. The Adhan is called, followed by the Iqamah and the first prayer is offered. Then, immediately after finishing the first prayer, the second Iqamah is called, followed by offering the second prayer.