The weather can bring welcome refreshment to your exertions.
Apart from really heavy, unseasonably cold downpours, running or jogging in the rain can be more pleasant than in the dry. The cooled air is denser, so you get more oxygen in each breath, and you lose less moisture through sweat if your skin is being repeatedly cooled. As ever, you do need the right clothing. Modern sports fabrics are excellent at wicking moisture away from your skin without becoming waterlogged.
When grip and visibility at altitude is not so important, such as in hiking (as opposed to, say, fell-walking or rock-climbing), rainfall is no problem if you're properly dressed. It can also help you keep cool in summer.
For all outdoor activities in the rain, there's an added reward in wait when you finish: getting dry. Why not combine your sport with a pub meal or finish at your favourite café? Children can also enjoy this kind of activity.
But if you can't face dragging yourself or your kids into the downpour, there are plenty of indoor activities that will keep all ages active, from soft-play areas and ball pools to trampolining, five-a-side football, swimming and indoor racket sports like squash and badminton.
Make the most of nature's playground.