For the first time since last winter, a few raindrops were heard on the roof early last Monday morning. It was over by the time I realized that the odd and unfamiliar noise really was that of raindrops. By the time the sun came up, everything was dry. I do not even know if these few raindrops could be considered to be the first rain of the season. There were a few similar raindrops on my windshield a while back, but they were dismissed as such; merely a few random raindrops rather than a confirmed rain shower.
That is how our climate works here. The Santa Clara Valley is in a chaparral climate. Much of Southern California is in a desert climate. We do not get much rain, and it is almost exclusive to a limited rainy season that is centered around winter.
Dust and crud that accumulates on foliage through the long dry season tends to stay there until the rain rinses it away. Oddly, many native plants do not mind, and a few seem to appreciate it. Some have tomentum (fuzz) on their leaves that collects dust, particularly during the warmest and driest summer weather when foliage is most sensitive to desiccation and scorch. Others have sticky foliage that does the same. However, such foliage is remarkably efficient at allowing such crud to rinse away in the first rain. Both deciduous foliage that will be shed shortly after the rainy season starts, and evergreen foliage that will be replaced through winter, seem to prefer to start the rainy season clean. Is this just coincidental, or do the plants intentionally collect dust and crud to shade and insulate their foliage through the harshest summer weather, and then wash up for a good sunning at the last minute?