Why Is My Cat Sneezing?

Cats can get allergies too.  A quick visit to the vet and an antibiotic or allergy med might be in order.

Your cat may have feline upper respiratory infection.  This is a disease with both viral and bacterial components.  Other causes can include nasal foreign body, nasal masses, or tooth root infections.  Have your cat examined by a veterinarian.  Appropriate treatment can start once a diagnosis has been made.

Feline upper respiratory complex is a common cause of sneezing.  This is due to various viruses and sometimes bacteria.  If your cat stops eating/drinking, becomes lethargic, or has nasal discharge it needs to be examined by a veterinarian.  Sneezing with no other signs will likely resolve in 1-2 weeks and is related to viral infection.  
If your cat is a curious cat he may have sniffed something, dust etc., that has caused a sneezing attack.

Upper respiratory infections, or "kitty colds" is the main reason for cat's sneezing. There may be some sort of object  is present in the nostrils of the cat. Take the cat's temperature if it is 102.5F then it is normal and if it is over 103.5 then you should take the cat to vet. I don't recommend you give her some thing at home. The infection can go worst if not treated in time.

Sounds like the kitty has something up her nose. Sounds like it.has it stopped yet ?
Or is this hair balls..

Cats can develop allergies, and even respiratory illnesses.  My cat sneezes often, and she is ok.  There are times where a cat may have a flurry of sneezes, just like we do, if an irritant is in the nose.  But if this seems different to you-or continues, or new symptoms occur- call your vet,

Upper respiratory infection, antibiotics will clear it up in 2 weeks.

Your cat could have allergies.

Most probably it is because she has caught cold due to wandering in cold air or there might be another reason.