with whom COLLINS, Justice, joins concurring in part and dissenting in part.
I concur with the court’s conclusion that the Superior Court erred in entering a summary judgment in favor of the plaintiffs. I also agree that the lease language is ambiguous, and that relevant extrinsic evidence is admissible to aid the trial court in construing the contract. Further, the trial court’s construction of the lease is entitled to a deferential review. See Titcomb v. Saco Mobile Home Sales, Inc., 544 A.2d 754, 757 (Me.1988); Pelletier v. Jordan Assoc., 523 A.2d 1385, 1386 (Me.1987). In this case, however, the parties agree that all the extrinsic evidence that is available has been submitted to the Superior Court. In my view that evidence cannot rationally support a finding of any breach of contract by Sherwin-Williams, and entitles Sherwin-Williams to a summary judgment. Therefore, I respectfully dissent from the court’s decision to remand to the Superior Court for trial.
When construing the intent of the parties to interpret an ambiguous contract term, a court gives considerable weight to the conduct of the parties. See Blue Rock Indus. v. Raymond Int'l, Inc., 325 A.2d 66, 73 (Me. 1974) (court places great reliance on conduct of parties in construing ambiguous contractual term); Restatement (Second) of Contracts § 202(4) (1981); 17A Am.Jur.2d Contracts § 357 (1991). In this case, the evidence shows that it was the custom of Sherwin-Williams, in all of their stores, for a period of approximately thirty years, to define retail sales as sales to household) or personal use customers, and wholesale 'sales as sales to business or nonresidential customers. Moreover, it is undisputed that plaintiffs accepted payments under the lease for twenty-one years, and agreed to several extensions of the lease without objecting to or attempting to renegotiate it, or objecting to the practice of Sherwin-Williams’ method of allocating retail and wholesale sales.
Thus, the only evidence in the record to aid the factfinder in construing this ambigú*732ous lease supports the construction advanced by Sherwin-Williams. Plaintiffs have produced no evidence in support of the construction of the lease they contend must be adopted. Because they have the burden to prove their allegations that Sherwin-Williams breached the lease, and because Sherwin-Williams would be entitled to a judgment as a matter of law at trial if the plaintiffs presented nothing more than was before the court at the time of the entry of the summary judgment, Sherwin-Williams is entitled to a summary judgment. H.E.P. Dev. Group, Inc. v. Nelson, 606 A.2d 774, 776 (Me.1992); see M.R.Civ.P. 50(c).
I would vacate and remand to the Superior Court for entry of judgment for Sherwin-Williams.