There are 2 separate issues: crossing times zones and changes in climate between countries.
Both are much easier to deal with when using basal bolus / MDI regime than bimodal insulin. On basal bolus you can have as many meals at you need in a day, which may last much longer than 24 hours when crossing time zones. My personal record is 5 when flying from UK to Santiago in Chile. I last flew to Australia / New Zealand before diagnosis. As I take 2 shots per day of long acting insulin, it's relatively easy to shift times between time zones. I find that a digital watch with dual time function is useful - I leave one time set to home [or destination if staying a long time] and the other changes to whatever zone I'm in, so I don't miss transport connections etc.
Changes in climate do affect insulin requirements - typically, both hot & humid and very cold and / or windy can mean you need less insulin than in more benign conditions. But other factors come into play eg you may be more or less physically active, you may lose appetite in hot weather, diet may be completely different etc. I've led expeditions in Costa Rica, Chile, Falklands and South Georgia since diagnosis, as well as travelling independently in Dominican Republic, Ecuador, Chile, Argentina, Morocco, Jordan, Iceland, much of western Europe etc. I love all food, especially Latin American, Scandinavian and Arab food, so eat completely differently in those areas than I do in UK. First trips after diagnosis were short trips to relatives in France and with a friend to Belgium, then within 8 months, I led a month long expedition to Costa Rica.
