Weather is a major factor throughout phase 1. If the weather is perfect and you don't see anyone working at your site, don't start thinking they are at someone else's site watching the concrete dry. A quick example ... If dirt needs to be brought in from off-site, the dirt needs to be in relatively good condition - if it has been rained on recently, it may take a few days to dry out (if it isn't given time to dry out a bit, you will essentially be getting loads of mud instead of dirt). There are also obvious reasons the excavators won't be on your site working - if it is (or has been) raining hard.