We are just passing 30mm for the day as I write. The summer's global cyclical pattern has set up such that, for example, western USA and Canada are having exceptional heat, whereas east US is cooler, and that jet stream pattern continues across the Atlantic to give us, especially eastern UK, cool and wet conditions. As a gardener I appreciate it after the driest April on record (the only precipitation that fell in the whole month here was snow!).
To show how localised it is - I can see it raining very hard about 3 miles from my front door, but dry as a bone here.
It's not especially localised - there is heavy rain associated with a small low pressure and convergence zone over very large parts of southern England but, equally, some places have missed the showers, which is in the nature of showers.