The second blessing of the Amidah refers to manifestations of G-d’s power. One of those manifestations has to do with weather. During the winter months (in Israel), beginning with the afternoon of Shemini Atzeret in the fall to the first day of Pesach in the spring, we recite “mashiv haruach umorid hagashem,” “Who causes the wind to blow and the rain to fall.” You’ll find those words in small print, to signify that they are not always recited.

In recent years, it has become increasingly customary to add the words “morid hatal” “who causes the dew to fall” during the summer months, between Pesach and Shemini Atzeret. You won’t find those words in the regular Sim Shalom prayer book, edited in the 1980’s. In the Shabbat Sim Shalom, edited much later, you’ll find an asterisk pointing out that “some add” “morid hatal.”

Why the change? “Morid hatal” was originally only a Sefardic custom among Jews in the Middle East, who were especially sensitive to the importance of dew in a desert climate. Many of the first Ashkenazi settlers were Chasidim, who follow the Sefardic nusach (why is a separate story). So when non-chasidic Ashkenazi Jews came to Israel, particularly in the 1920’s and 30’s, there was already an Ashkenazi community reciting “morid hatal.” So it basically became the standard Israeli nusach for Sefardim and Ashkenazim.

Over recent decades, as the Jewish communities of America and Israel have grown closer, Israeli customs have started to have an impact on American Jews. Changing attitudes toward kitniyot on Pesach is one example. Morid hatal is another. And I fully expect that in the not too distant future, morid hatal will simply be considered standard, rather than an option.

Which to my mind is a good thing. We are now learning, scientifically, of the tremendous impact of dew on the ecological wellbeing of plants in desert climates. Dew prevents transpiration, and fosters photosynthesis, which allows plants to withstand even the driest conditions. Although only a fraction of the water used by plants in any given year, dew punches far above its weight, and is essential for survival.

So recognizing it as a miracle, and thanking G-d for it, is only fitting.