A party must perform its obligations:
(a) if a time is fixed by or determinable from the contract, at that time;
(b) if a period of time is fixed by or determinable from the contract, at any time within that period unless circumstances indicate that the other party is to choose a time;
(c) in any other case, within a reasonable time after the conclusion of the contract.
With a view to determining when a contractual obligation is to be performed, this Article, which is inspired by Article 33 CISG, distinguishes three situations. The first is where the contract stipulates the precise time for performance or makes it determinable. If the contract does not specify a precise moment but a period of time for performing, any time during that period chosen by the performing party will be acceptable unless circumstances indicate that the other party is to choose the time. Finally, in all other cases, performance is due within a reasonable time.
1. A offers to advise B in the latter’s plans to buy computer equipment and software and it is agreed that A’s experts will visit B “in May”. It is in principle for A to announce when precisely in May that visit will take place. The circumstances may however leave the option to B, as would be the case if the contract expressly left to B the choice of the precise dates, or where, for example, it was understood that some of B’s staff who are often absent on business trips must be present when A’s experts arrive (see Article 6.1.1(b)).
2. A, a building contractor, encounters unusual difficulties when excavating a site and needs special equipment to continue the work which it does not have. A immediately telephones B, another contractor, who has the necessary equipment and agrees to lend it to A. Nothing however is said as to when the equipment should be delivered to A. Performance is then to take place “within a reasonable time” in the circumstances. Since the work has been interrupted because of the above-mentioned difficulties, A urgently needs to receive the equipment and in such a case “within a reasonable time” probably means that performance is due almost immediately (see Article 6.1.1(c)).