Short answer. A deadline. Article 1193 makes an obligation with a day certain demandable when that day comes, and a day certain is one that must necessarily come, even if you do not know when. A month that will certainly arrive is a period, not a condition.
What the law says
A day certain is understood to be that which must necessarily come, although it may not be known when. If the uncertainty consists in whether the day will come or not, the obligation is conditional
Civil Code, Article 1193 — Obligations With a Period; Day Certain. Read the full provision →
Period or condition: the test
Article 1193 supplies the dividing line: A day certain is understood to be that which must necessarily come, although it may not be known when. If the uncertainty consists in whether the day will come or not, the obligation is conditional, and is governed by the rules on conditions instead. Certainty of occurrence is the test, not certainty of date. Next month will come. So will the death of a named person, or the end of the rainy season. What is uncertain is whether a permit will issue, whether a third party will buy, whether a shipment clears — those are conditions.
What being a period gets you
Two things. Article 1193 makes the obligation demandable when the day comes, so you need prove nothing beyond the calendar. And Article 1169 makes the obligor incur in delay from the time you demand fulfilment judicially or extrajudicially — which is why a deadline that passes should be met with a dated letter, not a phone call. Once he is in delay, Article 1170 makes him liable for damages, and Article 1165 puts even fortuitous loss on an obligor who delays. A condition would give you none of that until the uncertain event happened.
Vague is not the same as conditional
Next month is imprecise, but imprecision does not turn a period into a condition. The risk it creates is different: a court may have to fix the exact day, since a term that leaves the moment of performance to be determined can require judicial fixing before the obligation is demandable. That takes time you would rather spend enforcing. The cure is drafting — a date, or a stated number of days from a defined event. Where the wording is already signed, look at what the parties did: schedules, purchase orders and the supplier's own written commitments usually pin the month down to a day.
Resolutory periods, and loss before the day
The article also covers the mirror image: obligations with a resolutory period take effect at once but terminate when the day certain arrives. A supply arrangement running until year-end is enforceable now and simply stops then — no notice required, which is worth knowing before you plan around a renewal nobody has agreed to. Article 1194 handles what happens if the thing is lost, damaged or improved before the day arrives: the rules in Article 1189 apply, so loss without the debtor's fault extinguishes the obligation and deterioration without fault is borne by the creditor.
Cases citing this provision
These Supreme Court decisions cite the provision above. We list them so you can read them yourself; the summaries of what each decided are not ours to give.
- Toyo Seat Philippines Corporation/Yoshihiro Takahama vs. Annabelle C. Velasco, et al, G.R. No. 240774, March 3, 2021 — read the decision on LawPhil →
- Maynilad Water Services, Inc. vs. The Secretary of the Department of Environment and Natural, G.R. No. 202897 / G.R. No. 206823 / G.R. No. 207969, August 6, 2019 — read the decision on LawPhil →
- Congregation of the Religious of the Virgin Mary, etc. vs. Emilio Orola, et al, G.R. No. 169790, April 30, 2008 — read the decision on LawPhil →
- Dr. Daniel Vazquez, et al. vs. Ayala Corporation, G.R. No. 149734, November 19, 2004 — read the decision on LawPhil →
Related provisions
- Civil Code, Article 1193 — Obligations With a Period; Day Certain
- Civil Code, Article 1194 — Loss Before the Period Arrives
- Civil Code, Article 1169 — Delay (Mora)
- Civil Code, Article 1189 — Loss, Deterioration, Improvement Pending a Suspensive Condition