Bob D:
Applying a wax in cold weather, while not ideal, can be done IF it is the ambient environment is dry. On a cold, humid (AKA rainy or foggy) day, forget it. Waxes tend to cloud up on days like this and are difficult to remove.
Hints for applying waxes in cool weather:
Indoor waxing, eat up a car panel with halogen light lamps (they throw off a lot of heat). Or use a hair dryer or heating gun to warm up a panel. Or best is to have a propane torpedo space heater (Reddy heater) because they generate large quantities of heat (BTUs). Waxing outdoors, if it is a sunny day, you can TRY to use that as a heat source especially now (late spring/early fall) when sun angles are more direct, even late in the afternoon.
One BIG mistake that many novice detailer make is over-application of wax, IE, using too much wax. This is especially true on a cool day. I still like the immediate wax-on-wax-off approach, but on a cool day you can wait awhile (3-5 minutes) for the wax to set up. That approach works well with Collinite waxes in my experience, so using Zymol waxes you may have to wait longer or just do some trial-and-error experimentation.