The rainy weather is a swarm cooker. A strong colony cramped inside a hive is really thinking "We think it is time to leave". Not much nectar coming in + crowded hive = swarm. When the weather breaks it is important to look for swarm cells.
I still don't have much nectar coming in. The nectar flow is taking its time of kicking into gear. The nectar flow will turn the swarm cooker on to low heat so I hope it starts soon.