Depends on whether your glove has a gaiter or not.
My gloves have an external gaiter that you can cinch on the outside of the jacket. So whether they are inside or out, it really makes no difference as water doesn't make it's way in as long as it is cinched down. It uses an elastic band with a sliding lock, strung through the outer edge of the cuff. Even in Houston rain, I haven't had any leaks yet.
There are some gloves that have an internal gaiter, like the Dainese Jerico, you can just tuck the goretex gaiter inside the jacket, and then roll the glove over the sleeve. So technically, the glove is both inside and outside your sleeve.
If you have a glove that doesn't know rain exists (but is inexplicably waterproof), and isn't designed with a cuff that does "something" about the weather, then tucking them inside your jacket when it rains is your best bet. However, I would say that you run just as much risk of the rain blowing into your sleeve, as you would the rain rolling into your glove. So it all really depends on how your sleeve fits around your gloves vs how your gloves fit around your sleeve.
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