It's very easy to control the rain. You just decide to re-discover 50 year old meccano skills by purchasing a lean-to greenhouse to stand next to the garage. The glass and aluminium structure lean-to arrives in 5 heavy well-sealed packs and at the bottom of the last pack you find the instruction booklet, clearly written by someone who knows greenhouses. This is an unfortunate decision on the part of the manufacturer. The booklet should be written by someone like me who does not know greenhouse construction and who needs large print, lots of diagrams and an indication of how long each stage should take.
I had decided to build a 3 sided brick base myself and derived a lot of pleasure in recycling bricks from other buildings in the garden, to create the precisely measured horizontal and vertical structure on which the frame would stand.(Spirit levels also need to be in large print with large bubbles). However, at that point the unfortunate rain control skill kicked in. So a job that should have taken about 5 days (grandpa pace) has actually taken 6 weeks. Every time I thought about building a section, the rain would begin.
This also meant that I have actually created the unwanted garden feature of a lake - which formed within my base walls. Fortunately the cement could not survive an attack by masonry drill and drain holes were created to drain away the reservoir, so removing the threat of water finding a way through hairline cracks in the backwall to invade items stored in the garage that do not respond well to damp.
Yesterday I re-hung the greenhouse door the right way round and moved 5 thriving outdoor tomato plants into their new home. Elsewhere in the garden other vegetables are also thriving thanks to generous water supplies. I am now definitely proposing to build an oudoor rainfed irrigation pond over the next 2 months .. in the hope that we will have the frustration of wall-to-wall sunshine.