In Japan, the 30th of June is;

NagoshinoHarae
A shrine ritual ‘’Ooharae’ is conducted on the last day of June and December to exorcise the sins and the uncleanness accumulated in the six months. Originally this ritual was held at the imperial court, today it is held at shrines nationwide. ‘’Ooharae’’ on 30th of June is also called ‘’NagoshinoHarae’’ or ‘’MinazukinoHarae’’ to cleanse our mind and body to pass the hot summer in Japan. ‘’Ooharae’’ on the 31st of December is called ‘’ToshigoenoHarae’’.

夏越の祓
6月と12月の晦日最終日には大祓といって、半年の間に身についた災厄の原因となる罪や穢れを祓う神事が行われます。もともとは宮中の行事でしたが、今は全国各地の神社で行われています。月30日の大祓は『夏越の祓』や『水無月の祓』ともいい、穢れを祓って心身を清め、暑い夏を健やかに過ごせるよう無病息災を願います。12月の大祓は『年越えの祓』といいます。

Minazuki
Azukibeans are on top of uirou, sweet rice jelly is called Minazuki. It is said that Azukibeans have the power to cast away evil spirits. The triangle shape also represents a talisman to protect us from evil spirits and to keep off all sorts of diseases.

みなづき水無月
夏越の祓につきものなのが『水無月』という菓子。氷に見立てた三角形のういろうに、魔除けの小豆を散らした和菓子。

出典　source of reference
英会話・英語スクール・異文化スタディーズ・英語・英会話出張講座Muse English Communication,
'2014年 06月 30日　夏越の祓',
viewed 9 February 2021,
https://coneikaiwa.exblog.jp/22224110/