So yesterday it was technically March in Vanadiel time and as luck would have it, I received two straight days with rain. Also, nobody had touched any mobs in two real-life days. (Parked character there)
During those two rainy game days, he did not morph. Is that because it's only a chance he'll morph during rain? Or will he only morph during April-June rainy days?
Either way today starts April so I guess I'll see what happens this week. Just frustrated because this is a really annoying spawn condition...