Weather-based water level question

[PolarBear56]

I've noticed recently that the water percentage varies throughout the day(s) despite there being no rain. As an example, last night the percentage was 150%, yet the system only ran for 87% this morning (back up to 150% at the time of this post). No rain for the last week nor is there any for the next week. Is this normal? Am I missing something?

Cheers!