Things to know about your pet chinchilla
Another take on * Heat * Humidity *

Chinchillas can actually take more cold then hot and humid.
Though I have never tested it with my chins, I have been told by many old timers that chins can handle down to Zero degrees Fahrenheit as long as their water does not freeze and they have a closed nest box with a buddy or two. They also must be free of drafts. I think this is an extreme and totally unnecessary for pet chins.
My chins have experienced mid fifty degree range (no drafts) and they are not phased a bit.
High heat and humidity is the most deadly. Be very careful if the temp gets much over 75 degrees F, and the humidity is rising. If the temp (over 70) and the relative humidity percent add together to make 150 or more, then you need to cool down the area and/or lower the humidity. The elevated heat/humidity can kill a chin very quickly, with in hours.
So in example, 70 degrees with 50% humidity is fine, that adds to only 120.... but 70 degrees and 80% humidity, this could be getting into a dangerous level. You need to cool the area AND bring down that humidity level with an air conditioner. Dehumidifiers also work, but once the temp is over 77 or more, taking humidity out of the air is NOT going to help.
Using a fan is NOT going to help. Chins dont cool themselves like we do...
Cold slate tiles in this type of weather only works for a few hours, if at all.... and frozen water bottles of ice are not going to help for long either, since it raises the humidity and can cause wet fur, matting of the coat and that can lead to fur fungus.
Now, oddly enough, if it is 60-70 degrees out, and it is raining and the humidity is 100%, this is not a problem. But when the rain stops and the sun comes out, the temps come up.... you better look at the formula again,
TEMP + Humidity = 150 (read -death to chins)

Dust baths, When we have that summer weather, high heat and humidity, even if you have AC, your chins will need a dust bath every other, if not every day, to keep the coat in shape and prevent the deadly side affects of the weather.