Blackout curtains, umbrella and a sleep mask!
Because I am out and about all day for work, I always carry an umbrella in my bag. I find the mini Fulton and Totes super-light ones are the best. They are small, light, and easy to carry with you at all times, but cope with all but the heaviest rain and wind. If it is really bucketing down, I usually take my large heavy-duty umbrella, but that does not happen often.
I could not survive without blackout curtains in summer, or an eye mask. I have venetian blinds inside my double-glazed windows, and two thick blackout curtains on each window, but the light still creeps in, so in recent years I have been using a sleep mask as well. These blackout curtains are also available in white, cream, beige, light grey and they block out the light just as well.