For the Ramadan fast in this example, intending it before true dawn is not necessary: an intention made before Nisf al-Nahar1 is sufficient for the stated intention requirement.
This does not remove the need for intention. Someone who has no fasting intention at all does not have a valid fast merely by remaining hungry from morning until evening. At least a general intention to fast is required.
Compare the Ramadan Qada fast already studied: its particular Qada intention was required before true dawn. The intention rule must stay with its own kind of fast.
1. Nisf al-Nahar: the half-day boundary used for this fasting intention rule; it is not simply the clock time 12:00.
- Intention Is Still Necessary