Most female cats go into heat for the first time at around 4–6 months of age, with many vets and pet experts citing about 5–6 months as typical puberty. Some kittens can come into heat as early as 3–4 months, while a few may not have their first heat until around 10–18 months, depending on breed and individual development.

Typical age range

  • Most female kittens reach sexual maturity and have their first heat between 5 and 9 months.
  • Many general pet guides summarize this as “around 6 months” for an average house cat.
  • Early cycling (3–4 months) is documented but considered on the early side and depends heavily on genetics and environment.

Breed and body factors

  • Shorthaired and especially Siamese-type cats often come into heat earlier, sometimes as early as 4 months.
  • Some longhaired or larger breeds may not show their first heat until 10–18 months of age.
  • Many sources note that puberty tends to begin when a kitten reaches roughly 80% of her adult body weight.

How often heats occur

  • Once puberty starts, an intact female can cycle into heat every few weeks during breeding season if she is not bred or spayed.
  • In many regions, cats are seasonally polyestrous, cycling repeatedly from roughly spring through autumn if not pregnant.

Practical takeaway for owners

  • Because first heat can happen as early as 4–5 months, many veterinarians now recommend spaying kittens before this age when possible.
  • If a young kitten starts showing heat behaviors (loud vocalizing, rolling, demanding affection, trying to escape), a prompt call to a vet is the safest next step to discuss timing of spay and care.

Bottom line: expect most female cats to go into heat for the first time around 4–6 months, but be prepared a little earlier, especially with fast- maturing or Siamese-type breeds.