26 CFR 1.989(b)-1: (b)-1 Definition of weighted average exchange rate.

For purposes of section 989(b)(3) and (4), the term “weighted average exchange rate” means the simple average of the daily exchange rates (determined by reference to a qualified source of exchange rates described in § 1.988-1(d)(1)), excluding weekends, holidays and any other nonbusiness days for the taxable year.