请教一道语法

gukangmat

05-1 

C39, The Northern Hemisphere faces the Sun most fully during the summer solstice which occurs in about June 22,

这里划线的which对吗?

Thanks!

水滴石穿

TOEFL考很久了，这些东西早忘了，请大家帮帮忙。

songyeonpp

occurs on
        about June 22