Ordinarily, the state need not prove the precise date on which an alleged offense occurs. (See PC 955.) CC 207 is the CALCRIM instruction on this point.
However, where the state charges a defendant with a criminal offense on occurring during particular dates — and when the dates form the basis of the defense (e.g., alibi — it is fundamentally improper to instruct the jury it may nevertheless convict the defendant if it finds the crime was committed reasonably close to the date(s) alleged. (See, e.g., People v. Jennings (1991) 53 Cal.3d 334, 358-359; People v. Jones (1973) 9 Cal.3d 546; People v. Barney, (1983), 143 Cal.App.3d at p. 490. See also generally People v. Gavin (1971) 21 Cal.App.3d 408, 415-420; People v. Whitacre (1926) 79 Cal.App. 27, 31-32.)
For briefing alleging ineffectiveness assistance of counsel for not objecting to CC 207 in light of the defendant’s alibi defense see People v. Scott 2014 WL 4655859 (Cal.), 7-13.