Yes — "is" is a Dolch Pre-Primer sight word. It follows regular phonics rules, but it's taught for instant, automatic recognition because it appears so often in early reading.
The sun is shining today.
"Is" is fully decodable — short i, then a hard "z" sound for the final s — but it shows up in nearly every early sentence a child reads. Because it's so common, kids are taught to recognize it instantly rather than pause to sound it out every single time.
Point out that the "s" in "is" sounds like "z", not like the "s" in "bus" — a small but useful detail for spelling it correctly later.
Word Wizard teaches "is" with Flash Cards, Listen & Pick, Spell It, and Write It — four game modes that turn repetition into play.
See "is" with its picture, syllables, and example sentence — with native audio.
Hear "is" spoken aloud and pick it out from similar-looking words.
Build "is" letter by letter from shuffled tiles.
Word Wizard turns sight word practice into a game — Flash Cards, Listen & Pick, Spell It and Write It, from Pre-K through Grade 5.