Can bright green avocados be ripe? I very rarely buy avocado, but now I happen to have two of them in my kitchen. 

I'm used to ripe avocado having this colour:



Now, mine are more brightly green, like this:



They aren't very soft, so I guess they aren't ripe yet, but I'm wondering if the colour will change or if this is just a matter of which variety of avocado it is?
Most avocado's are the Hass variety, which will go very dark when ripe

It look like you have bought a Reed or maybe Gwen variety. They are perfectly fine. Their skin colour will not significantly change as they ripen, so to check, gently squeeze near the point, and if it is soft it is ripe. If not a few days by the window at room temperature will fix it