快晴

1. Origins, structure, and basic meaning

• Structure: Written 快晴 and read かいせい, it means perfectly clear weather with little or no cloud.
• Basic usage: It is used for an ideal picnic sky and sunshine that dries laundry.

2. Common pitfalls and similar expressions

• More than absence of rain
  • The word positively describes clear sky and visibility, not merely dry conditions.