Mosquito season in Howard County, MD: when it starts and ends
Mosquito months in Howard County
In a normal year mosquito season in Howard County, MD starts around March 30 and ends around November 8, about 32 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Howard County, and when
- Start tipping out standing water weekly by March 16.
- Book any yard treatment for late March, ahead of the July peak.
- Repellent can go away after November 8.
- 1 West Nile case since 2016 (last 2018): you should use repellent at dusk June to August, more so if over 60.
Howard County against the rest of MD
Howard County has the 10th longest season of 24 MD counties, at 223 days against 235 in Wicomico County and 175 in Garrett County. Its mean temperature is 56.7°F.
- Worcester County: March 29 to November 11 (227 days, 0 WNV)
- Baltimore County: March 30 to November 9 (223 days, 26 WNV)
- Caroline County: April 1 to November 9 (222 days, 0 WNV)
- Queen Anne's County: April 1 to November 8 (221 days, 0 WNV)
West Nile in Howard County
From 1999 to 2025, CDC ArboNET counted 8 human West Nile cases in Howard County (5 neuroinvasive) across 6 years. The worst was 2003 with 3; the latest was 2018.
More: how the dates are worked out · when mosquitoes go away for the winter.