you can dry sift in the tropics (where it's high humidity most of the time) but you have to pick your day wisely, use material that is months old, pre-chilled and sift small amounts at a time, if there is the slightest hint of resin smudging, then it's the wrong day....but with a room that is made as freezing cold as possible with an air-con (and a humidifier if you have it) and a refrigerator for pre-chilling the plant material, it can be done.