May and September is the best time to visit North Asia
The temperature is pleasant during this time and the weather conditions are mostly stable making it easier to travel.
The temperatures are quite high during this time. The entire region is quite hot except for the mountains. This is also the rainy season which makes the environment a bit muggy. If you're looking for budget travel, this is a good time to visit as North Asia won't be too crowded.
This is the most comfortable time to travel. The temperatures are pleasantly warm. There is limited amount of rainfall making it easier to travel. However, this is also typhoon season. Although, one could expect heavy rain in Mongolia.
The winters in this region are incredibly cold. However, it is a good time to snowboard, ski, and skate. It is important to pack enough warm clothing and snow shoes.
The weather is pleasant during this time. Nevertheless, it is advised to carry a light sweater as the evenings could be a bit chilly. The flowers are in bloom and the scenery is breathtaking. Unfortunately, there could be unpredictable snowstorms in Mongolia during this time. However, these are the driest months of Taiwan making it the best time to visit.