Whales are only present from Jan - mid March

Late winter to early Spring the Pueblo closes for about ten weeks. - Official Taos Pueblo website. This closure is due in part to both seasonal and resident accommodations.

The Park is closed from Mid April to Mid October due to monsoon rains during which the Brahmaputra breaks its banks.

only has tours from April to September

Boats sail May-Sept: "The island can only be reached by a small boat on a calm summer day" .."yet trips are often blown out by sea conditions"
See en.wikivoyage.org

Can be visited all year, but OUV is derived from "The annual flood-tide, which pulses through the wetland system every year, revitalizes ecosystems and is a critical life-force during the peak of the Botswana’s dry season (June/July)"

charter flights only between June to September and the rivers would be frozen in winter so rafting/canoeing is out of the question - which are the only two realistic ways to access it

Butterflies are only present from November to March

No dive tours will take place during Columbia's heaviest rainy season ~ May/June

"filled in the rainy season to create temporary lagoons of various colours, shapes, sizes and depths. ... presents its best scenery when the lagoons reach their maximum volume, creating rare beauty" (AB ev) - Best time to visit is May - September, after the rains (wikivoyage)

"The Sanctuary is closed for three months of the year because of the impossibility of moving about during the rainy season" (UNEP-WCMC) / "Ouvert de novembre à juin, meilleure période de décembre à mars." (see link)
See www.saintlouisdusenegal.com

Usually open from October to May, depending on the monsoon.