how late can i pray fajr

The time to pray Fajr starts at true dawn (the beginning of twilight) and lasts until the sun begins to rise. It is preferred to pray Fajr soon after its start time without much delay while it is still dark. However, one can pray Fajr any time up until the sun actually starts to rise. Praying after the sun has begun to rise is not permitted until the sun has fully risen (about 20-30 minutes after sunrise). If missed, it should be prayed as soon as possible after waking up. In summary, the latest time to pray Fajr is just before sunrise when the sun starts rising. The preferred time is early in the Fajr time window but praying until right before sunrise is valid.