In order to daven Shacharit “at its time,” one should finish Shemoneh Esrei before the end of four proportional hours of the morning.[1] This is one third of the time between sunrise and sunset (according to some, one third of the time between alot hashachar and tzeit hakochavim, approximately seventy-two minutes before sunrise and after sunset, respectively). However, the gemara[2] teaches that one does receive some credit for tefilla after “the time” of Shacharit.
The gemara compares this late tefilla to the concept of tashlumin. Tashlumin is making up for a missed tefilla by doubling Shemoneh Esrei at the following tefilla. Because of this comparison and the rules pertaining to tashlumin, some Rishonim say that late tefilla applies only if one missed the time by mistake or because of extenuating circumstances.[3] Most say that, until the time of Mincha, the late tefilla is not tashlumim and may be recited even by one who was late intentionally. However, poskim advise that it is best to have in mind that, in case it is too late, the davening should be considered an additional, voluntary one (tefillat nedava).[4]
Chatzot, astronomical noon, is the latest of all opinions for the Shemoneh Esrei of Shacharit. (This information is included in some good calendars; be careful to factor in Daylight Savings Time.) In theory, one may daven Mincha then, although, in practice, we wait one half-hour to be on the safe side. At this point, Shacharit is no longer an option except as tashlumin at Mincha.[5]
After chatzot, then, tashlumin at Mincha is applicable, provided that Shacharit was not missed intentionally (meizid). When one gets up that late, it is not always clear whether to categorize the lateness as accidental or deliberate. Certainly, if one overslept, tashlumin is allowed. If he woke up earlier and rolled over in bed, aiming to sleep beyond the time, it is presumably meizid. On the other hand, some people are not capable of any serious intent when they roll over in bed. (It is a sign of responsibility when one reaches the point in life when these types of borderline cases stop arising.)
When one davens between the end of “the time” of Shacharit and chatzot, the simple ruling is to omit the berachot before and after Kri’at Shema (Yotzer Or until Shema and Emet V’yatziv until Ga’al Yisrael).[6] The Bi’ur Halacha[7] raises the possibility that one might be justified to include these berachot in the tefilla until chatzot, if he was unable to do so earlier because of extenuating circumstances. However, the average late riser is hard-pressed to make this claim.