Any ideas?

charlie my weim cross is 7 years old and just lately in the last couple of weeks his behaviour in the evening is rather odd.
about 7 oclock he wont leave me alone keeps on trying to sit on my lap if i go upstairs he follows me up one flight and will sit there till i come down from my room mon the next floor, yesterday my son was worried about him so bought him up to my room where he got on the bed and was trying to get behind me (was leaning on a pillow).
i have to saty outside with him when he needs to toilet as well,during the day hes fine and the other 3 arnt like this .
nothing has changed in the last couple of weeks and hes had a check up with vets
any ideas? thought it may have been the rain as he hates going out in it (but he doesnt get walked in rian anyway and if he needs the toilet i take a broly with us lol)

Two guesses on my part:

(1) something has spooked him and he is associating that time of the evening with it happening again. What it could be i have no idea - is he sound sensitive?

(2) particularly if you are having bad weather, presumably it has been getting darker in the evenings? (though still think 7pm might be a bit early for this to be the reason). Did the vet check his eyesight? I'm just wondering whether if it is starting to fail, he feels less secure when the light isn't as good.

You mention the rain - if it has been very heavy, it might have been the sound of it has been enough to spook him a bit.

Whatever it is, poor lad, I hope he soon gets over it.