I have been reading other threads in which incorrect information is being passed on the length of this period. Many equates the GT the time in which a beast is on the earth for 42 months Rev 13. The error stems from rightly understanding "what" is the GT. The GT is NOT a time of the wrath of Satan it is a time of the wrath of God. A period in which will never be seen like this again. To nail down the timing we look to Matthew 24 sequence of events and specifically the AOD.

Matt 24
15 When ye therefore shall see the abomination of desolation, spoken of by Daniel the prophet, stand in the holy place, (whoso readeth, let him understand

So what does Daniel say about this event?

Dan 12
11 And from the time that the daily sacrifice shall be taken away, and the abomination that maketh desolate set up, there shall be a thousand two hundred and ninety days.
12 Blessed is he that waiteth, and cometh to the thousand three hundred and five and thirty days.
13 But go thou thy way till the end be: for thou shalt rest, and stand in thy lot at the end of the days.

So Daniel states that on the 1290th day the AOD occurs. Thus Matt 24:15 occurs at day 1290. Also Daniel states there are only 45 days left afterwards till day 1335 and the end. So then Matt 24:16 till verse 30 are only 45 days. Thus the GT can be no longer than 45 days.

It is my belief the GT is the wrath of God contained in the vial judgements which are probably poured out in the last week.