All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
First of all, we would like to point out that our website does not provide its own prayer time service; it merely displays the most popular prayer time services in the Muslim world. They are five:
1) The University of Islamic Sciences in Karachi
2) The Islamic Society of North America (ISNA)
3) The Muslim World League (MWL)
4) Umm Al-Qura University
5) The Egyptian General Survey Authority
Perhaps the questioner did not notice that. The default prayer time displayed on our website is that of Umm Al-Qura University, which is cited by the questioner.
The observations of the dear questioner are correct; it is one of the oldest and widely used prayer time services. The likelihood of error increases as we move away from the equator - like in northern Europe and North America. If the questioner checked the other prayer time services on the website that were previously mentioned, she would find that the closest to Umm Al-Qura is that of the Islamic Society of North America (ISNA). However, the Fajr prayer according to Umm Al-Qura is one hour and a half ahead of the prayer time according to ISNA. As for the rest of the prayers, the time difference is about two hours (114 minutes). If the questioner followed these prayer time services, the problem is eliminated.
The best prayer time service that we recommend for the inhabitants of northern Europe and North America who do not have the ability to determine the accurate prayer times is the prayer time service of the Islamic Society of North America (ISNA).
For further information, please refer to Fataawa 13950 and 83588.
Allaah Knows best.