At their best in May
The months each trek's sources call the best.

Prashar Lakeपराशर झील
Himachal · Mandi

Kareri Lakeकरेरी झील
Himachal · Kangra

Bhrigu Lakeभृगु झील
Himachal · Kullu

Ali–Bedni Bugyalआली–बेदिनी बुग्याल
Uttarakhand · Chamoli

Phulara Ridgeफुलारा रिज
Uttarakhand · Uttarkashi

Kheergangaखीरगंगा
Himachal · Kullu

Madmaheshwarमदमहेश्वर
Uttarakhand · Rudraprayag

Panchachuli Baseपंचाचूली बेस कैंप
Uttarakhand · Pithoragarh

Sar Passसर पास
Himachal · Kullu

Doditalडोडीताल
Uttarakhand · Uttarkashi

Gaumukh Tapovanगौमुख–तपोवन
Uttarakhand · Uttarkashi

Pindari Glacierपिंडारी ग्लेशियर
Uttarakhand · Bageshwar

Kafni Glacierकफनी ग्लेशियर
Uttarakhand · Bageshwar

Kedartalकेदारताल
Uttarakhand · Uttarkashi

Dzongriज़ोंगरी
Sikkim & Darjeeling · West Sikkim

Roopkundरूपकुण्ड
Uttarakhand · Chamoli

Rupin Passरुपिन पास
Himachal · Uttarkashi–Kinnaur

Buran Ghatiबुरान घाटी
Himachal · Shimla–Kinnaur

Satopanth Talसतोपंथ ताल
Uttarakhand · Chamoli

Green Lakeग्रीन लेक
Sikkim & Darjeeling · Mangan

Bali Passबाली पास
Uttarakhand · Uttarkashi

Bailey Trail (Tawang)Bailey Trail
Northeast · West Kameng–Tawang

Sandakphuसन्दकफू
Sikkim & Darjeeling · Darjeeling
Also possible in May
Doable, but not the peak season: expect snow, rain or heat, as each trek page explains.

Harishchandragadहरिश्चंद्रगड
Western Ghats · Ahilyanagar

Rajmachiराजमाची
Western Ghats · Pune

David Scott TrailDavid Scott
Northeast · East Khasi Hills

Beas Kundब्यास कुंड
Himachal · Kullu

Dayara Bugyalदयारा बुग्याल
Uttarakhand · Uttarkashi

Har Ki Dunहर की दून
Uttarakhand · Uttarkashi

Dzükou ValleyDzükou
Northeast · Kohima

Pin Parvati Passपिन पार्वती पास
Himachal · Kullu–Spiti

Chopta Chandrashilaचंद्रशिला
Uttarakhand · Rudraprayag