Plain and simple he is not into you. Rain has never stopped anyone from seeing anyone, that was a terrible excuse to let someone down easy that you just don't find attractive. Respect yourself and don't play by his rules and go at his pace....make your own rules and pace and if he is interested he will do what it takes.
I would agree with the sentiment, but she actually mentioned the rain initially, not him.
Okay so, if it was raining hard as hell, roads slippery like heck, you would go out on a date, in the hard pouring rain, driving and possibly crashing your car?
Yes, I wouldn't let rain stop me at all. Do you have monsoons or something with widespread flooding? It rains on a relatively regular basis here, it's no big deal. You just learn to deal with it.
People drive every time it rains and whilst I'm sure that statistically road accidents will increase, the chances of being in an accident is still pretty rare. IMO it's pretty paranoid to assume that there will be an accident. People continue to drive every single time it rains.
Whilst there is a chance that he was attempting to sleep with you (which is of course is fine [and so is you being weary] - I and many others consider it an essential, natural part of building a relationship), there is also a chance that he did actually want to make a go of it.
From what I'm reading there though, if I did want to make a go of it and you put the date off because of potential rain from a weather forecast, then I'd maybe consider that you weren't very interested. It sounded to me like you were stalling. Perhaps he considers that an issue?
*Edit: I've just read the other post about him finishing at 12pm so you couldn't go to, for example, a museum or zoo. It sounds to me like you're *massively* over analysing planning a date. His hours are hardly abnormal, and neither is going out in the rain. If it's too late for the zoo (and five hours sounds like ample time to me), then go somewhere else. If it's raining, go somewhere indoors.