An online friend asked me on another forum what is the best way to protect candles from the summer heat. He brought up the idea of storing them in the fridge. This is a wonderful idea, especially for taper, stick, emergency, or household candles.
Now, if you have the 7 day candles with the paper labels then you may not want to store these in the fridge due to possible condensation damage to the labels. If you have a stash of 7 day candles you are worried about you can try to store them in the coolest part of the house or else just keep them upright in an out of the way place. As long as they are not moved, tilted, or knocked over they will be fine. In the past when my AC was not so good I've found that 7 day candles left in the heat will still be good as long as they aren't moved and are kept upright. The only problem that develops is a slight oily surface to the tops of the candles.
Tapers or stick candles should definitely be kept in the fridge during the hot Summer months as these types of candles will warp easily in hot weather. In fact, I know that in the past that I've lost candles simply due to the drive home from the local shop as the weather was so hot. Condensation will not effect these candles.
Now, another tip in storing taper or stick candles is to either use a separate box per color candle or use a thick plastic bag or even aluminum foil to wrap your candles in. This will keep the colors from bleeding. Thin plastic bags are not good enough and the candles will bleed into each other. Candle color bleeding has nothing to do with the weather but heat may speed up the process.
So here are my recommendations of candles that can be stored in the fridge over the hot summer months:
Taper, Stick, or Household Candles
Any candle that is poured in glass, such as 7 day candles or jar candles can be kept in an out of the way place. Just be sure not to move them or tilt them.
Please keep in mind that the quality of the wax is a big factor with regard to how much heat candles can take before melting or deforming. Lower quality wax, such as the wax in most 7 day candles will melt faster than higher quality waxes.