Blessing of the Unicorn

At the start of each day roll a d100, on a 1-30 you look to the sky to see a double rainbow. Upon witnessing such a whimsical phenomenon, you gain that number of temporary hp equal to the amount rolled on the d100. This effect last until you take another long rest. Prerequisite: In order to get the chance to see a double rainbow, you must be outside, in the daytime, & in under the natural sky.