Rebooting the Jolla phone did not do the job for me: Jolla's own weather app always shows an all white screen.
This is under SailfishOS 1.1.6.27 with Meecast, meecast-demon, meecast-lockscreen and meecast-eventview installed in their recent versions from "Warehouse".
Unfortunately uninstalling meecast-eventview and rebooting did not bring Jolla's weather app back to life.

Anyway, as the flock of Meecast, meecast-demon, meecast-lockscreen and meecast-eventview is much nicer and provides more functionality compared to Jolla's weather app (and I liked OMweather on the N900 a lot), I keep all of them installed, although this setup renders Jolla's own weather app completely useless for me.
Besides that, Meecast, meecast-demon, meecast-lockscreen and meecast-eventview (each and every of them) work flawlessly.

Kudos for the really good work, vasvlad.