On the new moon of Tamuz Rabbi Jill Hammer writes:
The first of Tammuz is a day of exile, reminding us that from this point forward the sun will begin to creep from the sky, leaving the world in ever-greater darkness. Just as the first of Tevet (new moon after the winter solstice) is the beginning of the journey toward light, the first of Tammuz is the beginning of the journey into the dark.
In Jewish tradition, the summer solstice carries with it themes of closure (the mouth of the deep, the garden of Eden), exile (Adam and Eve, Moses), and loss (the animals' loss of speech), yet also the benevolence of nature and the Divine (the appearance of the water from the rock, the saving of the small animals, and the standing still of the sun). We meditate on grief, yet also on the world's abundance. Summer solstice is a day of paradox: maximum light, yet also a turn toward darkness.
המליך אות ח' וקשר לו כתר וצר בו סרטן בעולם ותמוז בשנה ורגל שמאל בנפש.
He produced ח [Chet], predominant in Sight, crowned, combined, and formed Cancer in the world, Tammuz in the year, and the left foot of the human.
(ב) וְהָאָ֗רֶץ הָיְתָ֥ה תֹ֙הוּ֙ וָבֹ֔הוּ וְחֹ֖שֶׁךְ עַל־פְּנֵ֣י תְה֑וֹם וְר֣וּחַ אֱלֹהִ֔ים מְרַחֶ֖פֶת עַל־פְּנֵ֥י הַמָּֽיִם׃ (ג) וַיֹּ֥אמֶר אֱלֹהִ֖ים יְהִ֣י א֑וֹר וַֽיְהִי־אֽוֹר׃ (ד) וַיַּ֧רְא אֱלֹהִ֛ים אֶת־הָא֖וֹר כִּי־ט֑וֹב וַיַּבְדֵּ֣ל אֱלֹהִ֔ים בֵּ֥ין הָא֖וֹר וּבֵ֥ין הַחֹֽשֶׁךְ׃
(2) the earth being unformed and void, with darkness over the surface of the deep and a wind from God sweeping over the water— (3) God said, “Let there be light”; and there was light. (4) God saw that the light was good, and God separated the light from the darkness.