Two comets will be visible in the western sky in May.
Comet C/2001 Q4 will sweep northward from the southwestern sky after sunset. It can be seen moving from Canis Major (the Big Dog) in the beginning of May, near the star Procyon in Canis Minor (the Little Dog) by May 10, and over the stars Castor and Pollux in Gemini (the Twins) for the last half of May.

Comet C/2002 T7 moves through the constellation Pisces (the Fishes) in the predawn eastern sky at the beginning of the month. It will pass behind the sun and reappear in the western sky after sunset for the last ten days of May passing eastward through Canis Major (the Big Dog). In June, it can be seen passing south under the Leo (the Lion.)