Ideally, the morning bedikah is performed upon getting out of bed. Although it should be delayed until sunrise, a bedikah performed as early as alot hashachar (dawn) is acceptable. The morning bedikah may be performed until chatzot (halachic mid-day), at which point the halachic morning ends.

Please note that, although it is ideal (lechat'chila) halachic practice to perform two bedikot per day, the clean days remain valid even if only one bedikah is performed per day, whether in the morning or afternoon.