Best months to put a flea collar on your dog

Using a flea collar should not be based solely on intuition, but on understanding when parasites are most active in your area. The activity of fleas, ticks, mosquitoes, and sandflies varies according to season, temperature, and humidity. While in warm climates the risk is almost constant, in many regions there are seasonal peaks that require reinforced protection.

Knowing the key months to place or replace the collar is essential to ensure your dog is protected before parasite activity begins, preventing infection or infestation.

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Flea collar usage calendar for dogs

Factors that determine when to put a flea collar on your dog

There is no single date valid for all regions, as parasite activity depends on several factors:

  • Climate: mild temperatures and high humidity favor parasite proliferation.
  • Season: spring and summer are peak activity times, but in warm climates protection should be maintained year-round.
  • Collar duration: some models protect for 4, 6, or 8 months, which affects placement planning.
  • Type of predominant parasite: the calendar may vary depending on whether the main goal is to prevent fleas, ticks, or sandflies that transmit leishmaniasis.

Recommended calendar by season

In general, in temperate climates such as most of the Iberian Peninsula, this is the recommended schedule:

  1. Spring (March–May): put the collar on in early March so it’s active when parasite season begins.
  2. Summer (June–August): keep protection, as this is the highest-risk period, especially for fleas, ticks, and sandflies.
  3. Autumn (September–November): in warm areas, keep active protection until November to prevent late infestations.
  4. Winter (December–February): in cold regions the risk is low, but in coastal or warm areas year-round protection is advised.

In regions with mild winters, such as the Mediterranean, it’s safest to keep a flea collar on all year round.

Best months to use flea collar on dogs
Tips for planning flea collar replacement by month

Tips to plan collar replacement by month

Planning collar replacement properly is key to avoiding unprotected periods. Here are some tips:

  • Put the collar on 7–10 days before the expected start of parasite season in your area.
  • If using a 6-month collar, plan two replacements a year: March and September.
  • If using an 8-month collar, a single replacement in early March covers the whole risk cycle.
  • In warm or humid areas, keep the collar on year-round and replace it when its duration ends.
  • Mark the installation date on a calendar to avoid forgetting replacements.

With proper organization, you’ll avoid vulnerable periods where your dog could be exposed.

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Common mistakes when deciding when to put on a flea collar

Many infestations occur because of mistakes in the usage calendar. The most common include:

  • Putting it on after parasite season has already started.
  • Not replacing it on time when its effectiveness expires.
  • Removing it in winter in warm areas where parasites remain active.
  • Not adjusting the schedule to the specific climate of your area.
  • Assuming the collar protects if it’s damaged or worn out.

Avoiding these mistakes ensures your dog stays protected all year round from common threats.

Common mistakes when using a flea collar by season

Putting a flea collar on at the right time is essential to protect your dog from parasites like fleas, ticks, and mosquitoes that transmit leishmaniasis. However, many owners make seasonal and maintenance-related mistakes that drastically reduce the collar’s effectiveness.

  • Putting it on too late: waiting until peak heat leaves the dog unprotected during the first weeks of parasite activity.
  • Removing the collar in winter without assessing risk: in mild climates, parasites can remain active all year.
  • Not considering activation time: many collars need 1–2 weeks to fully distribute the active ingredient.
  • Reusing the same collar for multiple seasons: even if it looks fine, the active ingredient loses effectiveness after the manufacturer’s stated duration.
  • Not adapting to climate changes: warm springs or mild winters can advance or extend the risk season.
  • Relying only on a standard calendar: each region has its own parasite activity pattern, so local information is key.

Avoiding these mistakes and planning collar use according to climate and local parasite activity is the best way to keep your dog protected year-round.

Frequently asked questions about when to use flea collars

What month should I put on a flea collar?

In temperate climates, early March is ideal to cover the whole spring and summer season. In warm or humid areas, it’s best to keep it on year-round.

Is it necessary in winter?

In cold areas, winter risk is low and some owners remove it. However, in coastal or southern areas where parasites remain active, keeping it on is recommended.

Can it be used year-round?

Yes, especially in regions with mild or warm climates. This ensures there are no gaps in protection.

When should I put the collar on to prevent leishmaniasis?

Sandflies, which transmit leishmaniasis, are most active from May to October. Place the collar in late April or early May for protection from the start.

What if I put the collar on late?

If placed after parasite activity begins, your dog may already have been exposed, and in the case of leishmaniasis or Lyme disease, infection may have occurred.

Should I combine the collar with other methods?

In high-risk areas, it’s advisable to combine it with spot-on treatments or repellent sprays under veterinary supervision for added protection.