I live in San Francisco, which is an extremely temperate climate. We also have some of the most consistent water in the country because it comes from pristine mountain snowfall in the Sierra Nevada mountains. This makes my personal acne treatment regimen predictable and even. However, when I travel, I tend to notice changes in my skin.
For instance, I just went to Pennsylvania to visit my mom and dad last week. Weather is far more extreme on the East Coast than it is here in San Francisco. It was cold one day and warm and humid on another day. Also, the water there tends to be different from what my skin is used to here on the West Coast. Weather and water changes, combined with the dry plane cabin on the flight to Pennsylvania, made my skin a bit dryer than usual, and I had to compensate with more moisturizer for the first few days I spent back East.
Your skin may react differently depending on the climate into which you travel and the water with which you wash at that location. Plane cabins may exacerbate dryness as well. All of this should not prove to be a big problem because judicious application of the Regimen should keep you clear. Simply adjust the amount of moisturizer you use if your skin becomes dryer than it is at home. If your skin becomes oilier than usual, simply stay consistent with the amount of moisturizer you use, and wait it out for a few days. Your skin should get back to normal quickly. Do not stop using moisturizer. The shock to your skin caused by removing the moisturizer step of the Regimen may cause a breakout. If for whatever reason an unexpected breakout starts to rear its head, stay calm. The best remedy is to get super strict with your Regimen application and you should be back to normal in no time.