I am convinced that ads run during the working day when we are open for bookings are more valuable than ads run overnight and weekends. My belief is that I want the client to see, click and book in one action. We do not sell product online so can only make sales when we are open. Of course, having ads run at other times must be of some value, but given a zero-sum-game (ie fixed budget), am I right to spend more in the daytime and less in the evenings, night and weekends? Can someone please tell me if the huge volume of clicks on a Sunday is more likely to be casual browsing or of real sales potential?
When you are testing, you should probably set your campaign's delivery method to "Show ads evenly over time" during the testing phase so that you get data across the whole time period.
You might think about running an alternate landing page "off hours" with a different phone number on it - then when you're back open during the week, keep tabs on how many people come in via that line as opposed to the regular phone number. It won't be exact, but it might give you more information than you have now.
But as the saying goes, "your mileage may vary".
I noticed that in a retail campaign of ours. 3 out of 5 people would most of the time land up on our website but buy either later that day or within the week. My assumption is that they were browsing other websites to check products and price.
Maybe you can get some analytics (google analytics is free and can be integrated with your adwords account) and see if it help understand traffic a little more.