The Cat’s Love Calendar: How Long Are Cats In Heat?

Cat Conditions, Cats

Last Updated - December 12, 2023

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In the world of feline companionship, the unmistakable call of a cat in heat is a sound that most pet owners are bound to encounter at some point in their journey. While it may be a routine aspect of a cat's life, the experience can perplex those who have never encountered it before.

A female cat in heat, or the estrous cycle, is a natural biological process that unspayed female cats will experience at some point in their life. This phase is marked by a series of distinctive behaviors and physical changes that can be puzzling to even the most seasoned cat owner. However, by gaining insight into the science behind it and learning how to navigate these moments with patience and knowledge, you can ensure the well-being of your beloved pet and maintain harmony in your household.

In this blog post below, we will share how long cats are in heat, as well as what you need to know about indoor and outdoor cats in heat if you cannot get your cat spayed.

How Long Are Cats In Heat?

On average, a cat's heat cycle, scientifically called estrus, spans approximately 4 to 7 days. However, as with any biological process, there's room for variation in the cat heat cycle. A female cat in heat may experience a shorter cycle lasting 1 to 2 days, while others may remain in the heat stage for as long as ten days. The estrous cycle's specific length hinges on various factors, including the cat's age, breed, overall health, and environmental conditions. Only female cats that reach sexual maturity will experience a heat cycle.

The estrus cycle of a female cat unfolds in distinct phases:

Proestrus (1-2 days)

Proestrus marks the initial stage when a cat is in heat. While this phase is relatively short, it is a precursor to the following more intense estrus stage. During proestrus, some subtle changes in behavior may become evident. The cat in heat may become more affectionate towards her owner, seeking attention and physical contact. This behavior can be seen as an early sign of her impending heat. However, it's important to acknowledge that she is currently not receptive to mating. Proestrus is more about preparing her body for potential reproduction.

Furthermore, a cat in heat may exhibit restlessness, often pacing or circling, and increased vocalization. This vocalization may signal to nearby intact male cats, but she will not mate during this phase. Proestrus is when the cat's body is gearing up for the main event, estrus.

Estrus (4-7 days for most cats)

Estrus is the primary and most recognizable phase of the heat cycle and typically lasts for up to seven days. During this phase, a female cat in heat becomes sexually receptive to male cats, and her behavior changes significantly. These changes result from hormonal shifts in her body, particularly increased estrogen levels.

Several noticeable behaviors and physical changes are associated with a cat in heat entering the estrus phase:

Loud Vocalization: Female cats in the estrus phase are known for their intense vocalization. The yowling and meowing can be quite persistent, and it's their way of signaling their availability to male cat partners.

Mating Position (Lordosis): A cat in heat adopts a distinctive mating position called "lordosis." During this period, female cats often arch their back, raise their hindquarters, and tilt their tail to one side, assuming a position that signifies their readiness for mating.

Rubbing and Affection: Most cats in heat may exhibit heightened affection towards their owners or objects, often rubbing themselves against furniture, walls, or even people. Other cats may be grumpy and want to be alone.

Increased Appetite: Sometimes, a cat in heat will experience a notable increase in appetite during estrus. This is a normal response to the hormonal changes occurring in their bodies.

It's essential to note that a cat's heat can be intense for both the cat and its owner due to the changes in behavior and the potential to attract male cats.

During the estrus phase, a female cat in heat will emit pheromones that can attract male cats from a considerable distance and lead to unwanted pregnancy. This is why, when a cat is in heat, it's crucial to keep her indoors to prevent unwanted pregnancies.

Knowing that a female cat can become pregnant as early as her first heat cycle is important. To keep an overly young cat in heat from unwanted pregnancy, separate her from male cats - even if they are all young litter mates.

Interestrus (1-2 weeks)

Interestrus is a relatively calm period following a cat's heat cycle. During this phase, the cat is not in heat and reverts to her typical behavior. The intense behaviors associated with estrus subside, and she may resume her regular routines, showing reduced interest in mating or vocalization. Interestrus is a time when the cat's hormonal levels stabilize.

Unlike human females, who shed their uterine lining after the period of fertility has passed, a cat in heat who does not mate and conceive will reabsorb their uterine lining.


Anestrus is the phase between the heat cycle when the cat is not in heat. The duration of anestrus can vary widely and depends on factors such as the cat's age, breed, and environmental conditions. During anestrus, the cat's reproductive system is relatively inactive, and she is not actively seeking mating partners. This phase offers a break from the intense behaviors linked to being in heat.

How Often Do Indoor Female Cats Go Into Heat Cycle?

Indoor female cats, like outdoor cats, can vary in the frequency of their cycles. However, indoor cats generally do not follow the same seasonal pattern as outdoor cats due to controlled environmental conditions.

An indoor cat typically goes into heat every two to three weeks. They are more likely to experience heat year-round, also known as continuous or persistent estrus, than outdoor female cats. This phenomenon is primarily due to the controlled environment and consistent lighting conditions that indoor cats typically enjoy.

Continuous estrus in female cats can concern both the cat and the owner. It can lead to persistent vocalization, restlessness, and behavioral changes. To address this issue, owners often consult with veterinarians who may recommend getting their cat spayed, hormone therapy, or other medical interventions to regulate the estrus cycle and prevent continuous cycles.

Here's a closer look at why indoor female cats go into heat so frequently:

Consistent Lighting and Temperature

Indoor cats are exposed to consistent artificial lighting and temperature conditions throughout the year. Unlike outdoor cats that experience natural variations in day length and temperature with changing seasons, cats that live indoors are subject to artificial lighting that remains relatively constant. This consistent lighting can disrupt their natural hormonal cycles, potentially leading to irregular or continuous estrus. In short, they don't experience seasonal cycles that would otherwise cue them into the ideal times for going into heat, becoming pregnant, and giving birth.

Reduced Exposure to Male Cats

A female cat living indoors has limited or no access to a male cat, which can lead to persistent estrus. In outdoor settings, a female cat in heat can encounter male cats, mate, and then experience a period of reproductive rest after giving birth. Indoor female cats, however, are often isolated from potential male cat mates, leading to ongoing heat cycles.

Stress and Environmental Factors

Stress and changes in the indoor environment can also influence a cat's estrus cycle. Stressors such as moving to a new home, adding new pets, or alterations in routine can disturb the hormonal balance in a cat, potentially leading to irregular heat cycles.

Health Conditions

Certain medical conditions have the potential to impact a cat's hormonal balance and may lead to a prolonged estrus phase. These conditions may include ovarian cysts or tumors, mammary cancer, hormonal imbalances, or reproductive tract infections.

Individual Variation

Factors such as age, breed, and individual biology can influence the frequency and intensity of cycles in indoor cats. Certain cats may experience shorter or longer intervals between their heat cycles. A female cat typically reaches sexual maturity and experiences her first heat cycle between 4 and 7 months of age.

How Often Do Outdoor Female Cats Go Into Heat Cycle?

Outdoor cats typically go into heat or experience estrus during the breeding season, usually in spring and summer. The frequency of heat cycles for outdoor cats can vary depending on various factors, such as geographical location, environmental conditions, and individual characteristics. Here are some key points to consider regarding how often outdoor cats go into heat:

Seasonal Variation

Outdoor cats are influenced by natural factors such as daylight length and temperature, which signal the onset of the breeding and mating season. In regions with distinct seasons, outdoor cats tend to go into heat more frequently during the spring and summer when environmental conditions are conducive to mating.

Geographical Location

The frequency of cycles in outdoor cats can vary by location. In regions with milder climates, outdoor cats may experience more extended breeding seasons or even sporadic heat cycles throughout the year. In contrast, areas with harsh winters may have shorter and more intense breeding seasons.


On average, outdoor cats may go into heat every two to three weeks during the breeding season. Nevertheless, the frequency of heat cycles can vary significantly among individual cats. Some outdoor cats may experience heat every few weeks or even more frequently, while others may have longer intervals between their cycles.

Population Density

After the peak of the breeding season, outdoor cats may experience a reduction in the frequency of their cycles. Factors such as the availability of food and the presence of potential mates in the environment can notably influence the frequency of a cat's heat cycles.

Environmental Factors

Environmental stressors, such as changes in food availability, social dynamics with other cats, and access to potential mates, can influence the timing and frequency of cycles in outdoor cats.

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About the Author

Doctor of veterinary medicine with extensive experience in animal welfare with a strong interest in feline medicine and plans to pursue ABVP-Feline specialty board certification. A key member of many local veterinary associations and avid reader of animal related science journals and studies.