Affects of weather on cigars?

• 
  
  It sounds as if your humidor is not large enough for the amount of cigars you have and that the calibration is off. You did'nt mention haow long you leave them in your truck. But if you leave them in your truck for than a couple of days put them in a sealed plastic bag. What is happening is your cigars are drying out.
• 
  
• 
  
  At first, check the humidity level at least every two weeks to ensure that the humidity does not vary.
  
• 
  
  Once a month (more often in arid weather conditions) add distilled water to the humidifier.
  
• 
  
  Other sources, such as tap water, contain minerals and chlorine that can clog the humidifier’s pores and inhibit operation. 
  
• 
  
  Store your humidor in a cool, dry place to prevent mold growth. Avoid placing your cigars in direct sunlight. If the temperature and humidity get too high, cigars can develop a potentially damaging fungus or mold.
  
• 
  
  Another hazard of cigars stored in too hot or humid an environment is an infestation of worms called lacioderma. The worms lay eggs inside cigars and burrow out, forming tiny holes in the wrapper and metamorphosing into tiny, brown beetles. If you discover the presence of worm holes in your cigars, remove and destroy the affected cigars immediately, and then carefully inspect all the cigars in your humidor for signs of infestation.
  
• 
  
  To check if the hygrometer is reading correctly, use the salt method to test its calibration.

To check if the hygrometer is reading correctly, you can purchase a calibration kit for best results. Another way to test the calibration of your hygrometer is the salt method. You will need to:

1. 
   Place a teaspoon of salt in a bottle cap or small cup and dampen it with a few drops of water (without dissolving it).
2. 
   Carefully place the wet salt and the hygrometer inside a see-through container and close tightly. You can use a zip lock bag provided it seals well and you leave some air inside as well.
3. 
   Let it sit for at least 6 hours and note the reading on the hygrometer without opening the container. The hygrometer should should read 75%. The difference is how much your hygrometer is off. For example, if your hygrometer reads 70% during the salt method test this means that to obtain the real humidity level you should add 5 points.
4. 
   If you have an analog hygrometer, you can correct the reading. You will need to adjust the needle to the 75% mark by turning the screw on the back using a small screwdriver. Your hygrometer is now ready to be placed inside your humidor.

Cigars are made with natural leaves. Those leaves are accustomed to 60 to 70 degree weather. The cold weather dries them out and therefore makes the cigar brittle. You have two problems here. The cigars are drying out and therefore become very delicate and subject to damage. The second problem is that you are cutting too much off the cigar's head. When you cut too much the cigar will unravel as the head is made to hold it all together. You should only be cutting about 1/8th of an inch off the cigar's head. There's an option for those that do not know how much to cut off when clipping the cigar's head. The Perfect cigar cutters are available from Cuban Crafters and authorized retailers throughout the world. They are designed to cut the exact amount of tobacco from the head of any cigar, including Figurado and Torpedo shaped cigars without any guessing. There are 2 models available: The CC-23   and the CC-24 made for larger cigars.

With these patented cutters you will never have to guess how much to cut off again. The xikar is a decent cutter but it is made for force, not precision.

My guess is that you area probably cutting off too much and taking all of the cap and some of the body too. That would explain the unraveling. As for the splitting, you're probably not too dry but rather too wet. The over humidified tobacco expands very rapidly when it heats up, causing the wrapper to split. I would suggest you check the calibration of your hygrometer and adjust as needed. I'd bet money it's reading low and you sticks are sitting in too much moisture.