While petrichor is pleasant after a rain, according to the wiki article on geosmin it appears to also indicate poor water quality [0]. So perhaps the evolved s

While petrichor is pleasant after a rain, according to the wiki article on geosmin it appears to also indicate poor water quality [0]. So perhaps the evolved sensitivity is to avoid stagnant water, rather than to seek recent rainfall. After all, for prehistoric hominids local recent rainfall is pretty obvious, and traveling large distances to distant rainfall is not usually practical. [0] https://en.wikipedia.org/wiki/Geosmin https://en.wikipedia.org/wiki/Geosmin