While it seems like it's probably best not to expose anything to extreme climates, will keeping a guitar/bass amplifier in a car for a day, in either hot or cold climates, have any short-term effects on its well-being? Long-term problems? Are there any special considerations for tube amplifiers?
I assume that an amplifier has travelled in various non-climate controlled transports, for longer durations, even before it gets to me (from manufacturers, to distributors, to retailers, etc.)
Related : Effects of keeping a guitar in the car