User blog comment:Xilinoc/Ch. 541 - THE BLADE AND ME 2/@comment-3230060-20130613145316/@comment-2186265-20130614181035

His inner world reflects the state his mind is in. When he's sad it rains. The reason the old man calls the Hollow Ichigo the source of Ichigo's despair was Ichigo was afraid of his second hollow form which prevented him from completing his hollowfication properly. As it was Ichigo's despair that caused his inner world to be flooded what he said was true.