Rime ice is typically formed under which temperature conditions?

Rime ice is primarily formed in conditions where supercooled water droplets are present, typically in the temperature range from 0º to -20º Celsius. When aircraft fly into clouds containing these supercooled droplets, the droplets can freeze upon contact with the aircraft surfaces, resulting in the formation of rime ice.

This process is most effective at temperatures between -10º and -20º because, within this range, the droplets remain supercooled enough to create the conditions required for rime ice formation, while also not being so cold that other types of ice, like clear ice, are more commonly formed.

Above 0º Celsius, ice does not form, while below -20º Celsius, the conditions are less conducive to the formation of rime ice due to changes in the nature and size of the droplets in the atmosphere. Therefore, the best temperature range for rime ice formation is indeed from -10º to -20º Celsius.