When Is NYC Pest Season?
Seasonal analysis of NYC rodent complaint cycles — which months see the most rat activity, and how much does it drop in winter? Computed from January 2023 – June 2026 (42 months) of NYC 311 data.
Seasonal averages based on 2023–2025 (three complete years). Pull date: 2026-06-25.
What is the average NYC rodent complaint count by season?
Averaged across 2023, 2024, and 2025 (three complete calendar years), NYC rodent complaint volume peaks in Summer (Jun–Aug) with an average of 3,946 complaints per month, and reaches its lowest point in Winter (Dec–Feb) at an average of 2,184 per month — a 1.8× seasonal amplitude.
This pattern is consistent with the biology of the Norway rat (Rattus norvegicus), NYC's dominant urban rodent species. The CDC and NYC DOHMH both document that rat foraging and burrow construction activity is most intense in warm months. Cold winters suppress outdoor activity without eliminating colonies — rats retreat to heated infrastructure (basements, subway tunnels, sewers), reducing visibility and 311 complaints.
Mar–May
3,355
avg complaints/month
Spring
Rising activity as temperatures warm
Jun–Aug
3,946
avg complaints/month
Summer
Peak rodent activity — outdoor foraging and burrow construction
Sep–Nov
2,854
avg complaints/month
Fall
Declining outdoor activity; rats migrate indoors
Dec–Feb
2,184
avg complaints/month
Winter
Winter nadir — cold suppresses foraging activity
Averages computed from 2023–2025 monthly data. Source: erm2-nwe9, complaint_type='Rodent'. Pull date: 2026-06-25. Full methodology →
Which specific months mark the start and end of pest season?
The all-time peak in our measured data window was August 2023 (4,559 complaints) — a record driven by the warm 2023 summer. The most recent winter low was February 2026 (1,183 complaints). The data consistently shows that rodent complaints begin rising in March–April as temperatures warm, peak in June–August, and decline sharply from October onward. NYC pest season typically spans approximately 6 months (April–September).
Season start
March–April
Complaints begin rising as temperatures climb above 10°C
Peak activity
June–August
Summer high — outdoor foraging, new burrow construction
Season end
October–November
Sharp drop as cold drives rats into heated structures
Note: "season" here refers to complaint volume, not absolute rat population. NYC's rat population does not disappear in winter — it shifts from outdoor to indoor environments, which may increase interior infestations even as 311 complaint volume drops. See the NYC DOHMH tenant/property owner guidance for year-round control recommendations.
How do the same months compare year over year?
The table below shows each January and July across 2023–2026, illustrating both the seasonal amplitude within each year and the year-over-year trend.
| Year | January (winter) | July (summer) |
|---|---|---|
| 2023 | 3,050 | 4,331 |
| 2024 | 2,870 | 4,204 |
| 2025 | 2,180 | 3,635 |
| 2026 (partial) | 1,336 | — |
Source: erm2-nwe9. 2026 July data not yet available at pull date 2026-06-25.