Weather this Sunday won't be terrific, but it shouldn't be terrible either, on lake Thun (according to meteoblue)
Is anyone up for having a walk from Spiez to Thun? Hike is described on
https://www.schweizmobil.ch/en/hiking-in-switzerland/routes/etappe-01755.html ; goal is to explore the garden town of Spiez and its Katzenstein lookout point, the church of Einigen, the city of Thun and its many castles.

Meeting point: let's meet at 10am at the ticket office of Spiez train station.

In case it rained, we can cut the hiking time by catching a bus from Spiez to Einigen, which seems to be the less interesting bit of the walk.