Akiehl: it is too early to predict what the trail conditions for hiking will be like on May 18 - 20. (Other than to say for sure that SP will be closed.) However, unless there is a late snow fall you should be okay on these routes on those dates. Of course you will need sturdy hiking boots and lots of layers, culminating in water proof. Hiking sticks would be very helpful. And I am assuming you are using some public transport assists along the way? It is quite a long way from Alpiglen to Trachsellauenen and the route from Alpiglen up and over the Kleine Scheidegg might well be closed (although you can take the train). Finally, it would be helpful for you to cut/paste and post this in a separate thread so as not to confuse the two topics.
Namrata, Unfortunately there is not such a site, at least that I have found. Also unfortunately it is not possible to predict very far in advance. Route openings are entirely dependent on weather -- how much snow has accumulated over the winter, late snow storms, etc. I have seen the high routes open as early as first week in June and as late as the first of July.
The routes that you saw as open May 20 are likely transport routes (bus, gondola, ski lift, etc) and not hiking routes. For example, you can get to First via ski gondola and enjoy the adventures there as early as 6 May but typically cannot hike the route from there to Bachalpsee until mid June.
I have used various sources to compile a list of operating dates for transports in the Jungfrau region which you may find helpful. Please note that all scheduled operating dates are weather-dependent
Wengernalpbahn (Lauterbrunnen to/from Kleine Scheidegg via Wengen train) runs year round.
Jungfrau Railway (between Kleine Scheidegg and Jungfraujoch) operates year round.
SchynigePlatte Bahn (train Wilderswil to Schynige Platte): operations resume 24 May 2017 and run until 26 October 2017 (note: the Schynige Platte to First hike is often closed until mid-June due to snow then closes again when the snow begins to fall)
Lauterbrunnen to Mürren via Grütschalp train and gondola: operates year round except 1 May to 5 May 2017, and a few dates in October and November. During these dates public transport to Mürren is available via the Schilthorn gondola only.
Schilthorn gondola (Stechelberg to Schilthorn via Gimmelwald and Mürren): operates year round except 24 April to 28 April 2017 and 13 November to 8 December 2017.
Männlichen gondola (from Wengen) until 2 April 2017 then reopens 20 May 2017. The gondola then runs until 22 October 2017. The lifts from Grindelwald Grund operate until 2 April then reopen 25 May until 22 October. 2017 (Note: the Männlichen to Kleine Scheidegg walk is possible during summer but is usually closed until mid-June due to snow)
Allmendhubel cog train (Mürren to Allmendhubel): operates year round except 18 April 2017 to 9 June 2017 and 16 October until 8 December 2017
First gondola (Grindelwald to First via Bort): operates until 17 April 2017, closed until 6 May 2017 then runs until mid to late October 2017
(Note: the First to Bachalpsee walk, accessible during summer season, is typically closed until mid-June due to snow)
Harder Kulm funicular operates from April to November. The only way to ascertain exact dates is to enter a query at www.sbb.ch: Interlaken Ost to Harder Kulm, insert your travel dates and see if you get a result. In 2017 it appears to start running 14 April.
And for those of you venturing at outing to Oechinensee lake above Kandersteg, the cable car operates on the following dates:
13 May 2017 – 16 June: 9:00 to 17:00
17 June 2017 – 10 September: 8:00 to 18:00
11 September – 22 October 2017: 9:00 to 17:00
Trümmelbach Falls typically opens from early April until November.
Lake Thun and Brienz cruises operate from April through mid to late October. Lake Brienz cruises have a limited schedule in spring and fall. To check operating dates and times use the route planner at fahrplan.bls.ch/index. html?travelMode=ship. The site is in German only but easy enough to navigate. For point of departure enter either Interlaken Ost (Lake Brienz) or Interlaken West (Lake Thun). For destination enter Brienz or Thun, respectively. Enter your date and desired time then available cruises will be displayed. You will also see a graphic that indicates stops in between but no information about arrival time is available. The ships are in dock for 5 minutes at most before continuing on to the next port.