In the 2005 movie, how long was the invasion before the aliens died of our viruses? I've seen the movie once and I'm curious as to how long the aliens were on earth.
In the 2005 "War of the Worlds" screenplay there's no canon explanation of the interval between the invasion and the first alien deaths from disease. It's merely described as;
In the original "The War of the Worlds" by H.G. Wells, the chapter heading for Book 2 : Chapter 6 is headed 'The Work of Fifteen Days' and indicates the destruction wrought by the aliens in the two weeks of their initial invasion. Our hero finds his first dead alien two days later.
I see no reason to assume that the film-makers departed from this timeline.
If the narrative of the film is to be believed roughly 72-96 hours (3-4 days) have transpired since the Tripods first broke through he ground in Jersey City and when Rachel and Ray arrive in Boston and see that they (the Tripods) are collapsing and their shields are failing.
How can this be determined?
While the H.G. Wells novel proposes that the events it relates happened over a fortnight, nothing in the film indicates that the entire affair lasted longer than 3-4 days at most.