Based on the grade you are using, checking the coefficient of linear thermal expansion.  It will depend on which stage your weld lines are formed. If you have a high molecular weight material and the weld area is during the initial stages of filling, the weld strength may be good in both climates. If your weld area is towards the end of filling,  a grade with higher elongation property may be helpful. If you have the problems  for assembly, you have to check the CLTE of both the matching surfaces. Without having the complete details, it would be very difficult to provide appropriate solution.

When you need to inject products, the mold temperature and melt temperature should be same irrespective of climate, so the environment at molding is concordant . If moisture is present, the weld strength would be low and you will notice surface defects at the same time. The molecular chain would break and the material strength would be low.The stresses developed due to climate change can cause problems. So, you have to analyze the problem whether it is in individual part or in an assembly. Experienced engineers from Green Vitality comcan offer the best solution when you in troubles.