I live in New England and twice a year experience 8-15 days of BG rollercoaster. During the rest of the year, can hold BG 100% TIR (Time In Range) , SD (Standard Deviation) of 18 mg/dl or better within a BG range of 55-150 6 AM to 10PM and BG range of 55-130 between 10 PM and 6AM for 30-day periods.
During two 2 periods I drop to between 96%-97% TIR and my SD goes up to 20.
The 2 periods are in the Fall season when we go from hot/warm Summer days to cold mornings and in the Spring when we go from cold Spring days to warm Summer morning days. The earliest indications are that in the Fall, there is a need to wear a light jacket in the morning to feel comfortably warm and in the Spring, it is the period when the sweater comes off.
The only other time climate change affects my BG more than temporarily is following a long flight (at least 13 hours) and going from an airplane-controlled climate to a very hot and humid climate like to Asia or Africa from the US or Europe. The effect then is short-lived at only about 4-6 hours but still noticeable and needs to be taken into account with adjusted insulin dose after last meal before landing.
Temporary climate changes would mostly be times such as taking a shower with a wide difference between ambient temperature and temperature of shower water and the effect goes away within 15 minutes.