One thing to note with outdoor coverage, 2.4GHz and 5GHz have roughly the same signal propagation in open air, so outdoor, 5GHz actually has pretty good coverage. HOWEVER, most routers have lower 5GHz radiated power than 2.4GHz. My WDR3600 at the same location line of sight, 5GHz is typically 6-7dB lower signal strength than 2.4GHz. My Archer C8 isn't quite as bad, but 5GHz is still typically 3-4dB lower than 2.4GHz, but this could be because of 5GHz beamforming on the router. Some of this is also perhaps attenuation from the signal penetrating the case of the devices I am using (phone, tablet, laptop) as well as the signal punching through the covering of the antennas (because, not bare metal). However, the rare of signal attenuation is the same (IE roughly 6dB per doubling of distance from client to base station antennas).
So outdoors you get a lot better coverage on 5GHz than you would indoors, but it still likely to be roughly 2/3 to half the range (because roughly 4-7dB lower signal). If you had bare metal antennas on both ends (or at least exposed antennas on the client, instead of inside of the chasis), the 2.4GHz and 5GHz range would most likely be pretty comparable.
In a window, even with internal antennas, on 5GHz, if the window is NOT low E coated, I'd expect you to be able to get a good connection out to at least 50ft and poor to fair maybe out to 100ft. If the window is low E coated, halve those distances.