With no weather active, Hurricane has an accuracy of 70%. In the rain, however, the accuracy of the attack is boosted. Serebii states that its accuracy becomes 100%.
This move has different accuracies depending upon the weather. In Rain, it has an accuracy of 100%. – Serebii.net AttackDex
Veekun and Psypoke both confirm this as well.
During Rain Dance, this move has 100% accuracy. – Veekun
During Rain Dance, it becomes 100% accurate. – Psypoke
However, Bulbapedia states that Hurricane "cannot miss" in the rain (emphasis mine).
Hurricane cannot miss when used during heavy rain, but has an accuracy of 50% during intense sunlight. – Bulbapedia
This is slightly unclear. It could be trying to state that Hurricane has a 100% accuracy and therefore cannot miss unless the attacker's accuracy or defender's evasion have been modified. It could also be trying to say Hurricane is unable to miss in the rain, similar to Aerial Ace and other similar moves. Does Hurricane have 100% accuracy in the rain, or can it not miss?