Sorry to see that Alice. Rain does make the blooms blast too if it came too much in a downpour, some rain shower is welcome from time to time. You are lucky you get rain at this time, my plants would love it here!
Since we don't have rain I end up watering everyday here even my Adeniums, since it is just too dry and our humidity is very low.
I want to say I would not worry as long as the caudex is staying firm and the leaves are growing well, but we have different reasons for growing this plant, some just want to see the fantastic caudex formations and some wants the blooms and of course we all hope to see its lovely summer blooms.
It is still early July, don't lose hope maybe as summer time progresses some more, it will still attempt to make some nice buds and blooms, just got to get that full sun and dry humidity it likes at this time.
I would be more worried if after the rains the caudex shows some mushiness, then you are going to have more problems, but if it is staying okay, then just got to be patient with it. And you did say it is a grafted Adenium, maybe that also affects the budding process.
