Mosquitoes in Winter: Are Dengue and Malaria Still a Risk?

Many people believe that once winter begins, mosquitoes vanish  and with them the threat of diseases like dengue and malaria. Cooler air and fewer standing puddles after the rains give a sense of safety. But the truth is more complex. While cold weather does slow down mosquito activity outdoors, it does not completely stop mosquitoes from surviving and spreading disease especially in urban areas with warm indoor spaces and persistent water sources.

Why Mosquitoes Don’t Just Disappear in Winter

Even when it’s cold outside, mosquitoes , especially species like Aedes aegypti and Anopheles, find ways to survive. Indoor environments like  kitchens, bathrooms, water storage tanks, flowerpots, water‑coolers  provide warmth and breeding opportunities. In fact, in many cities across India, public‑health data show that after‑monsoon and early winter months continue to record cases of dengue and malaria.

According to urban health surveillance reports from the National Vector Borne Disease Control Programme (NVBDCP)and local authorities, cases of both diseases have been reported well beyond the monsoon season, sometimes stretching into November and December. This shows that mosquitoes are capable of surviving mild winters or persisting inside homes.

Dengue & Malaria Cases Reported Even in Cold Months

In recent years, several Indian cities have documented dengue and malaria cases during winter. For example, in one urban area health officials reported that malaria cases had “almost stopped” outdoors because the cold made outdoor mosquitoes inactive  but dengue persisted, because indoor breeding sites remained active.

Similarly, surveillance data from the Delhi‑NCR region confirms that though disease incidence dips after monsoon, “residual breeding, urban microclimates, stalled vector control and human behaviour” can sustain transmission into cooler months.

These findings align with broader observations from public‑health programmes that stress the need for vigilance and mosquito‑control activities even after the rains end.

What the Government Advises: Vigilance Beyond Monsoon

Health authorities under NVBDCP and local municipal bodies routinely emphasize that elimination of water stagnation and elimination of breeding sites must continue after monsoon. In fact, post-monsoon anti-larval drives, house-to-house inspections, and public awareness campaigns are part of official strategy even as winters approach. Many community-focused initiatives, including field efforts supported by GCPL EMBED which has worked across 41 districts, reaching 3.74 million households and more than 58 million people quietly strengthen these government campaigns by helping families spot and eliminate hidden breeding sites during routine visits.

The message is clear: Seasonal patterns may shift, and climate variability means mosquitoes can survive longer than traditionally expected. So long as there is water, shelter, and human neglect, the risk of dengue and malaria remains, even in winter.

Conclusion

Winter may bring relief from heat and heavy rains but it is not a guarantee of safety from mosquitoes or mosquito‑borne diseases. Indoor water storage, forgotten containers, potted plants, and even small water‑holding items can become mosquito breeding grounds. The fact that public‑health data continues to show dengue and malaria cases into late autumn and early winter should serve as a wake‑up call.

If we want to stay safe through the season, we must maintain vigilance: keep water covered, check for breeding spots in and around homes, and support ongoing vector‑control and awareness efforts. Winter may slow mosquitoes down, but it doesn’t make them disappear.