Short answer. Between nine in the morning and two in the afternoon. The notice must specify the place, date and exact time, and the sale must fall inside that window. The parties may agree on the venue; without an agreement, real property is sold at the office of the clerk of court that issued the writ.
What the law says
The notice shall specify the place, date and exact time of the sale which should not be earlier than nine o'clock in the morning and not later than two o'clock in the afternoon.
Rule 39, Section 15 — Notice of sale of property on execution. Read the full provision →
What the law says
The place of the sale may be agreed upon by the parties.
Rule 39, Section 15 — Notice of sale of property on execution. Read the full provision →
The window is fixed by the Rules
Section 15 does not leave the timing of an execution sale to the convenience of whoever is conducting it. The notice must specify the place, the date and the exact time of the sale, and that time must not be earlier than nine o'clock in the morning nor later than two o'clock in the afternoon. Two obligations sit in that single sentence. The first is that the sale happens inside a defined daytime window. The second is that the exact time is announced in advance, in the notice itself, rather than being settled on the day.
Why the exact time is stated in advance
Requiring an exact time in the notice is what makes the rest of the notice regime useful. The twenty days of posting for real property, and the newspaper publication where the assessed value exceeds fifty thousand pesos, exist so that bidders and the owner can attend. A notice that named only a date would leave anyone relying on it to wait through an entire day, which is a practical way of thinning attendance at an auction. The owner is separately entitled to written notice at least three days before the sale, in the manner of personal service of pleadings.
Venue by agreement, and the default
As to place, the Rules give the parties the first word: the place of the sale may be agreed upon by the parties. Only in the absence of such an agreement does the default apply. Real property, and personal property not capable of manual delivery, are sold in the office of the clerk of court of the Regional Trial Court or the Municipal Trial Court which issued the writ, or which was designated by the appellate court. So an execution sale of land does not ordinarily happen on the land itself unless that is what the parties have agreed.
Personal property capable of manual delivery
The exception is property that can be physically handed over. For personal property capable of manual delivery, the sale shall be held in the place where the property is located. The logic is practical rather than technical: bidders can inspect what is in front of them, and the item can be turned over on the spot. The result is that a single execution can produce sales in more than one place, with movables sold where they sit and land sold at the clerk's office, each still inside the same nine to two window and each on the exact time stated in its notice.