Walther sighed as he felt sorry for the girl he already thought of as a little sister. The love of a red queen will never be reciprocated. Even if it is returned, it is not true love. Kinsey's feeling was already bound by the power of the 'charm' of the red queen.
Therefore, if one day Kinsey confess his feeling to Katie, it was not his own feeling, but it was a form of the charm's power.
"Hey, what happened? Jarvas said Katalina was crying at her cottage," stated Clodio.
"So, it's raining because of her crying? What should we do? We can't let her lifetime decreasing more than it had."
"No," Egon replied, carrying the log that was a sign of Katie's life.
"The circle hasn't reduced. This rain really comes from nature, not from her power."
One more reason why they choose a rainy day to perform the ritual. Because if it was raining already, Katie's power would not be active even if she cried no matter how hard she wept.