[¶ 1] Rhonda M. Reimche appealed from a divorce judgment awarding Keith R. Reimche custody of their son, Tyler, and from an order denying her motion for a new trial. We affirm.
[¶2] Keith and Rhonda were married in 1989. Tyler was born in 1990. Rhonda sued for divorce in 1994. Both parties sought custody of Tyler at trial on July 17, 1996. The trial court awarded custody of Tyler to Keith, and liberal visitation to Rhonda. The trial court denied Rhonda’s motion for a new trial and Rhonda appealed the judgment and the order denying her motion for a new trial.
I.
[¶ 3] Rhonda contends the trial court erred in denying her motion for a new trial on grounds of irregularity and surprise. Rhonda asserts Keith failed to supplement his December 1, 1994, interrogatory answer that he did “not want custody, just reasonable visitation.” She argues she was denied a fair trial because she was without sufficient notice of Keith’s intent to seek custody of Tyler.
[¶ 4] Rule 26(e)(2)(B), N.D.R.Civ.P., requires a party “seasonably to amend a previous response if the party ... knows that the response though correct when made is no longer true and the circumstances are such that a failure to amend the response is in substance a knowing concealment.” The purpose of the rule is to eliminate surprise at trial. Dewitz by Nuestel v. Emery, 508 N.W.2d 334, 339 (N.D.1993). To be seasonable, a supplemental response must be made a reasonable time before trial. Id. A determination of reasonableness is within the sound discretion of the trial judge. Id.
[¶ 5] On May 16, 1996, Rhonda’s attorney filed a certificate of non-readiness. On May 28, 1996, Keith’s attorney filed a responsive motion and brief, stating, in part, that “the only issue of contention between the parties is custody and visitation concerning the parties’ minor son, Tyler Justin Reimche.” In a letter of July 11, 1996, Keith’s attorney informed Rhonda’s attorney:
“As to visitation and custody, my client proposes the following:
“1. That Rhonda have custody on the condition that the minor child reside with Rhonda at Rhonda’s place of residence and that Rhonda resume primary caretaking duties. Also, that the minor child shall be clearly informed of his familial relationships. If these conditions are not met, Keith will seek custody at the trial scheduled for July 17,1996.”
In a letter of July 15,1996, two days prior to trial, Keith’s attorney formally supplemented Keith’s interrogatory answers by stating, “Yes, Keith is planning to seek custody based on the best interests of the child.”
[¶ 6] In a discussion following closing arguments at trial, Rhonda’s attorney said she received Keith’s July 11, 1996, proposal on the Friday or Monday before trial. The trial court asked the parties’ attorneys: “I am wondering procedurally if either party would feel disadvantaged because of the way they tried their case if I would interpret the pleadings as they are on their face and make a custody determination instead of assuming that custody had been waived by the Defendant.” Rhonda’s attorney replied that she would ask for the appointment of a guardian ad litem to “look into the allegations ... that Rhonda is not in fact raising her child” and “[t]o look into the relationship Tyler has with his father.” The trial court asked of Rhonda’s attorney: “[Bjeeause of Friday’s or Monday’s communication, did you do anything to react to that? Would you do anything differently?” Rhonda’s attorney re*793sponded: “Quite honestly, at that late notice, I didn’t know if I could even line up someone to interview the parties and interview the child, look at the child’s home, and be able to be here today.”
[¶ 7] The trial court ruled “that as of at least the first part of this week, all parties were clear that custody was an issue.” The court also determined that appointment of a guardian ad litem was not necessary:
“That as to the request to supplement the record by a report from the guardian ad litem, I tend to agree with Ms. Edward-son that the issues enumerated by Counsel Dillon that might be addressed by a guardian ad litem have been presented in court and subjected to cross examination. And as to those specific issues, frankly, the answers to those issues I don’t find necessarily determinative anyway. Most of the issues that have been presented or inquired about relate to questions that the Court doesn’t have.”
[¶ 8] In denying Rhonda’s motion for a new trial, the trial court noted that in a pretrial telephone conference with both attorneys on July 15, 1996, the court was informed Keith was pursuing custody, and was advised in chambers immediately before trial that Keith was seeldng custody. The court also noted that “[a]t neither conference did the Plaintiff express surprise or indicate she was not ready to proceed with the trial.”
[¶ 9] A continuance is the proper remedy for a party claiming unfair surprise. State v. VanNatta, 506 N.W.2d 63, 69 (N.D.1993); Williston Farm Equip., Inc. v. Steiger Tractor, Inc., 504 N.W.2d 545, 552 (N.D.1993). “A judgment will not ordinarily be reversed on appeal for surprise at the trial, where no request is made for a continuance at the time and there is no showing of inability to meet the situation.” North Dakota Pub. Svc. Comm’n v. Central States Grain, Inc., 371 N.W.2d 767, 780 (N.D.1985). As this court explained in Hamre v. Senger, 79 N.W.2d 41, 47 (N.D.1956):
“As a general rule, a party asking for a new trial on the ground of surprise at evidence must have indicated his surprise to the court at the time, and should not have proceeded with the trial and speculated on the chances of a favorable verdict, but should have asked for delay or a continuance to enable him to overcome the effect of such evidence.”
“A new trial will ordinarily not be granted for surprise or accident unless ... a new trial will probably result in a changed verdict.” Id. “A trial court’s denial of a motion for a new trial, or for relief from the judgment under Rules 59 and 60 is purely discretionary, and we will not disturb its decision on appeal unless there is an affirmative showing of a manifest abuse of discretion.” Frafjord v. Ell, 1997 N.D. 16, ¶ 5, 558 N.W.2d 848.
[¶ 10] Rhonda knew before trial that Keith was seeking custody of Tyler. She did not object or request a continuance. Rhonda did not show an “inability to meet the situation,” Central States Grain, Inc., 371 N.W.2d at 780, or that “a new trial will probably result in a changed verdict.” Hamre, 79 N.W.2d at 47. We conclude the trial court did not abuse its discretion in denying Rhonda’s motion for a new trial on the ground of irregularity or surprise.
II.
[¶ 11] Rhonda contends the trial court’s custody award is not supported by the weight of the evidence. We exercise a limited review, as “the trial court’s findings ‘come here well armed with the buckler and shield of ... [Rule] 52(a).’ ” Hirschkorn v. Severson, 319 N.W.2d 475, 479 (N.D.1982) (quoting Horton v. U.S. Steel Corp., 286 F.2d 710, 713 (5th Cir.1961)). Under Rule 52(a), N.D.R.Civ.P., a finding of fact will not be set aside unless it is clearly erroneous.
[¶ 12] “In a divorce proceeding, the trial court must award custody of the minor children based upon a determination of the best interests and welfare of the children.” Schestler v. Schestler, 486 N.W.2d 509, 512 (N.D.1992). “The trial court is vested with substantial discretion in matters of custody and in the determination of what is in the best interests of the children.” Id. A trial court’s custody determination is a finding of fact that will not be set aside on appeal unless it is clearly erroneous. Id. “A trial *794court’s findings of fact are presumptively correct.” Fenske v. Fenske, 542 N.W.2d 98, 102 (N.D.1996). “The complaining party bears the burden of demonstrating on appeal that a finding of fact is clearly erroneous.” Buzick v. Buzick, 542 N.W.2d 756, 758 (N.D.1996), In reviewing findings of fact, we must view the evidence in the light most favorable to the findings. Chaussee v. Thiel, 520 N.W.2d 789, 791 (N.D.1994). “A choice between two permissible views of the evidence is not clearly erroneous.” Id. “Simply because we might view the evidence differently does not entitle us to reverse the trial court.” Schestler, 486 N.W.2d at 512. A finding of fact is clearly erroneous only if the reviewing court on the entire evidence is left with a definite and firm conviction that a mistake has been made. Id.
[¶ 13] Our limited review of findings of fact recognizes that the trial court is in a better position to evaluate evidence than we are:
“This limited scope of review recognizes that the trial court, having had the opportunity to observe and assess the demeanor and credibility of the witnesses, is in a much better position to ascertain the true facts than an appellate court, which must rely on a cold record. We will not reexamine findings of fact made by the trial court upon conflicting evidence, and a choice between two permissible views of the weight of the evidence is not clearly erroneous. When reasonable evidence in the record supports the findings, we will not retry the case to substitute findings we might have made for those of the trial court.” (Citations omitted.)
Buzick, 542 N.W.2d at 758. See also Fenske, 542 N.W.2d at 102.
[¶ 14] The trial court found that Tyler, “since the separation of the parties, primarily has been in the care, custody and control of his maternal grandparents.” The trial court considered the factors listed in NDCC 14-09-06.2(1) for determining the best interests and welfare of the child. After stating its findings on the factors listed in NDCC 14-09-06.2(1), the trial court made its custody determination:
“12. That the Court finds the determination of child custody in this case is a close call. Based on the Court’s overview of the facts, the Court’s view of the de-meanors of the parties, the Court’s impression as to which party would pay the most attention to the child, the Court’s understanding from reviewing the file and the evidence that perhaps some of [Keith’s] inattention was caused by either legal or intentional frustration of visitation by [Rhonda], it is the Court’s finding that the best interests of the child is served by placement of the care, custody and control of the child with the father.”
In announcing its findings after trial, the court said Rhonda’s credibility “in the eyes of the Court is very questionable.” In denying Rhonda’s motion for a new trial, the trial court said Rhonda’s “apparent indifference to the child was a significant factor in the decision as well as demeanor of the parties.”
[¶ 15] Rhonda admitted lying on a number of occasions and, as the trial court observed, Rhonda’s “primary answer to any question was — whether it was relevant, not relevant, important or not important — was: I don’t recall.” There was evidence: (1) Tyler was living with Rhonda’s parents in Ray, while Rhonda lived in Stanley and visited Tyler in her parents’ home on days off from work;1 (2) Rhonda believes Tyler should make custody and visitation determinations; (3) Rhonda has never allowed Keith to take Tyler for overnight visitation;2 (4) Tyler was “excited to see” Keith when he visited; (5) If Keith were granted custody of Tyler, Tyler would be living with him, Keith would enroll Tyler *795in Sunday school, and Keith would not expect his family to be Tyler’s primary caregivers; and (6) If Keith were granted custody, “[t]here would be no problem” with visitation for Rhonda.
[¶ 16] The record evidence supports the trial court’s findings. Our review of the entire evidence has not left us with a definite and firm conviction that a mistake has been made. Rhonda has not met her burden of demonstrating that any of the trial court’s findings are clearly erroneous. Viewing the evidence in the light most favorable to the trial court’s findings, we conclude the trial court’s custody determination is not clearly erroneous.
[¶ 17] The judgment and the order denying the motion for a new trial are affirmed.
[¶ 18] VANDE WALLE, C.J., and NEUMANN, MARINÓ and SANDSTROM, JJ., concur.. Rhonda explained she had earlier been living in her grandmother's house, but ‘‘[t]he plumbing and the furnace went out two years ago,” and she does not commute daily to her work in Stanley because her parents’ pickup, which she had been driving, "broke down six months ago, roughly.” Rhonda testified she is planning to repair the pickup and is planning to get a home of her own.
. “Visitation between a child and her noncustodial parent is presumed to be in the best interests of the child” and is "a right of the child." Blotske v. Leidholm, 487 N.W.2d 607, 610 (N.D.1992).