Left science kits in trunk in extreme cold, should I be cautious?

Hi! Hopefully someone can help, I picked up a handful of unopened kids science kits about a month ago at a resale shop (mostly MEL science). Completely forgot they were in my trunk until now.

The temperatures here have gotten down around -6° F (-21.11° C) some days. They were a loose stack in my trunk, but I've placed them in a closed plastic tub at room temperature now. Is this something I should be cautious with? They appear to all still be sealed. I'd assume the kits now will be less effective or might not work correctly, but moreso just wanting to be safe.

Chemicals involved:

Zinc Sulfate, Methylene Blue, Potassium Hexacyanoferrate, Potassium Iodide, Sodium Hydrogen Sulfate, Sodium Thiosulfate, Urea, Calcium Chloride, Copper (II) sulfate, Magnesium, Ammonium Carbonate, Iron (II) Sulfate

Thank you for any help!