I've just realized that I've always read this Levantine verse with myopically British eyes. When I read of God sending rain to fall on the righteous I imagine the righteous shivering and saying, "Thanks a bunch!" But I live in a cold country with no shortage of rain. If I were in first-century Palestine, perhaps I'd think of the rain primarily as a blessing, irrigating crops and so forth. The sun and rain, rather than being used in contrast, as they normally are in English (sun good, rain bad - as per a million song lyrics), form a classic Psalmic doublet, saying the same thing twice in different ways. We enjoy not dying of drought just as much as we like not living in perpetual night.
This theory depends of course on the climate in that region in Jesus's time being much like it is today, where lack of water is a real problem. It may have been wetter then - a question for the palaeo-climatologists, I suppose. Either way, the thought that the reading of a verse might be dependent on the climate in which it is read pleases me.