It’s difficult to give accurate estimates of range and signal strength, because every situation is different.
As an example of the difficulty of estimating range: In situations in which a lot of radio-frequency equipment is in use (such as hospitals, law enforcement, fire station), this RF gear will interfere with WiFi signals and reduce range.
Of course, obstacles of any kind will reduce range, and direct line of sight is the best situation to produce the longest range. Obstacles adjacent to the line of sight will affect range, though less than obstacles in the line of sight.
Roofs, such as on a porch, pavilian, purgula etc. will also reduce range/signal strength even when you have a direct line of sight. If you step out from under the roof or pavilian, you will probably see an increase in signal strength.