If plans are thwarted by the weather here are some suggestions as what to do on a wet and windy day in the Lake District.
Maryport is on the Solway coast about half an hours drive from Keswick.
A popular destination is the Maryport Aquarium which is stocked with sea life from the Solway as well as a selection of sea creatures from more exotic parts.  They also have a have a lobster hatchery and the kids can get their picture taken with Larry the Lobster.  There is a café,  ice creams &  shop with lots of fish themed nik-naks.
If your Kids like a bit of adventure activity there is Clip and Climb and for older kids there is West Coast Indoor Karting .
Maryport has an interesting history, starting with the Romans 2000 years ago to the building of the Port in the 18th century and its subsequent Maritime & Industrial heritage. You can find out more  by visiting the Roman Museum & the Maritime Museum. Also check out the Shipping Brow Gallery which has a collection of Maritime paintings by 19th century artist William Mitchell and also works by local artist Percy Kelly.
If it has stopped raining take a walk around the harbour and marina and have a look at Maryport Lighthouse which is quite unique, made the early 19th century from Cast iron, one of the first of its type. Also walk along the ‘Sea Brows’ past the Roman museum and back along the prom.   Then stop for fish and chips on the Harbour or refreshment at one of the towns many Cafes or Pubs.