Rashi: Like ¹ in a dry spell in a desert, when crops dry and wither, so You will humble the clamor of foreigners.

Radak: Like a heat spell in an arid place, and a person has no shelter to escape it, so You humbled that clamor of foreigners and their multitude; they had no escape and shelter.

Malbim: The heat will dry the water and cease the flood.

Rashi: When it becomes overcast with clouds in a dry spell, everyone is happy.

Radak: The dryness will be for the Goyim like a dry spell in a desert, and for Yisrael a dry spell in the shade of a cloud. I.e. there will be great afflictions in these days for Goyim and Yisrael, like we wrote above (24:23). Yisrael will be saved - "Kol ha'Nimtza Chasuv ba'Sefer" (Daniel 12:1). For them, shade will cool the heat; Nochrim will be cut off and humbled due to it.

Malbim: It is shade of a cloud, which subdues (alleviates from) a heat spell.

Rashi: So the Tzadikim will sing loudly ¹ when tyrants are cut off and fall. "Zemir" is [cutting,] like "Lo Simzor" (Vayikra 25:4).

Radak: "Zemir" is cutting, like "v'Charmecha Lo Simzor." "Ya'aneh" is humbling, like "Le'anos Mipanai" (Shemos 10:3). "Aritzim" are Nochrim.

Malbim: The song of tyrants [rejoicing over their victory and Gevurah] will be subdued, just like shade of a cloud subdues a heat spell. I.e. the nature of Kedushah is to subdue evil, just like moisture subdues dryness, and vice-versa.