Same as the weather.

The division of administrative areas has nothing to do with climate!

Wenzhou is basically typical, and Shaanxi is really typical. Northern Shaanxi, Guanzhong and southern Shaanxi are completely different climates.

For the southeast region, the main basis for the division of provincial boundaries is "mountains and rivers", and Fujian and its surrounding areas have the natural barrier of Wuyishan. The central axis of a lateral branch (Yandang Mountain) extending eastward from Wuyishan becomes the dividing line between Fujian and Zhejiang.

In fact, Wenzhou and Ningde (Fujian) are already the dividing line between Ou dialect and Min dialect, and the northern part is greatly influenced by Wu dialect, while the southern part of Min dialect has no shadow of Wu dialect. In other words, Wenzhou Ningde can also be regarded as the dividing line of the cultural circle since ancient times.

Not to mention that there was a separate separatist regime in Fujian in history (Fujian in Five Dynasties and Ten Countries), but actually from the Tang Dynasty-only the Yuan Dynasty was around 100 years-the dividing line between Fujian and Zhejiang is basically the current position. In other words, this dividing line has been established for more than 300 years.