What to wear for a short excursion to Jungfraujoch and Mount Titlis in first wee...

I am 67 years old and my spouse 62 years young. We both are planning to go for a short excursion to Jungfraujoch in the first week of May by Cable Car followed by Cogwheel train and visit the Ice Palace and Sphinx Observatory Deck followed by lunch at Interlaken.

Next day we plan to visit Mount Titlis by the rotating cable car -Rotair and visit the cliff walk suspension bridge followed by a tour of Lucerne.

We don't intend to do any skiing at either place.

Kindly suggest what type of clothing and shoes we should pack for the above trips.

I'm less pessimistic compared the answer of @Willeke:

If there is sun, sun (radiation) is strong, so you may not need too many layers.

If it would be bad weather, sorry but you will not enjoy much and so you will not remain outdoor for long time (but it is magic walking in the clouds, where you may not full see your feet).

And on both case, you are not staying outdoor hours, and you will be near the building and so the restaurant to get warmer between short outdoor visits.

Just: get good shoes (and possibly a pair to change, if they become wet). And if you have more layers, the better: you can decide to wear one more. Unfortunately it takes baggage place (and maybe low use), so it is your decision.

If you go to Jungfrauhoch, I would not go to Titlis: both are touristy, but Titlis on a bad way. If you are near Jungfrauhoch, go to "Piz Gloria" (and so also a good view of a "Hobbit like valley", and in Lucerne: Pilatus: it is not so high, but Switzerland is not just glaciers).