Seasonal Termite Activity Patterns

Peak Swarming Season

Why spring matters: Most visible termite activity occurs in spring when reproductive swarmers emerge to start new colonies.

What to watch for:

• Swarming termites: Large numbers of winged termites around windows, doors, lights
• Discarded wings: Piles of shed wings on windowsills, near doors, or on floors
• Increased mud tube construction: Fresh tubes appearing on foundations
• Activity after rain: Swarms often triggered by warm, humid weather following rain

Typical swarming times:

• Subterranean termites: Daytime, usually mid-morning to afternoon
• Timing: Warm days (70°F+) after rain
• Duration: Swarms last 30-40 minutes typically
• Frequency: Multiple swarms possible over 2-3 week period

Regional Variations

• Southern states: Swarms begin as early as February
• Mid-Atlantic/Midwest: Peak in April-May
• Northern states: May-June swarming
• West Coast: Variable; often March-April

Spring Action Items

• Schedule annual inspection (if not done in fall)
• Watch for swarmers, especially after warm rain
• Check foundation perimeter for new mud tubes
• Document any swarming activity (date, time, location)
• Clear gutters and improve drainage before heavy rains

Peak Underground Activity

Why summer matters: Warm temperatures accelerate termite metabolism and colony growth. Peak feeding and tunneling activity.

What to watch for:

• Drywood swarmers: Late summer swarms (dusk, attracted to lights)
• Formosan swarmers: Massive evening swarms in May-June (southern states)
• Increased damage progression: Existing infestations expand faster
• Moisture-seeking behavior: Activity near irrigation, leaks, or humid areas

Drywood termite swarming:

• Timing: Late summer to early fall (August-October)
• Time of day: Dusk to evening
• Behavior: Attracted to lights; may swarm from inside structure
• Location: Common in coastal southern states, California

Summer Action Items

• Monitor irrigation systems (avoid overwatering near foundation)
• Keep mulch dry and away from foundation
• Watch for evening swarmers (drywood species)
• Maintain good ventilation in crawl spaces and attics
• Fix any plumbing leaks promptly
• Keep firewood away from structure

Preparation and Late Swarms

Why fall matters: Termites prepare for winter; late-season swarms possible; ideal inspection time before winter.

What to watch for:

• Late drywood swarms: Continued swarming in warm regions
• Colony consolidation: Termites move deeper into wood/soil
• Moisture accumulation: Fall rains create favorable conditions
• Damage becomes visible: Summer feeding may now show structural effects

Best inspection season:

• Activity still high enough to detect
• Easier access before winter weather
• Time to treat before spring swarms
• Identify issues before holiday season

Fall Action Items

• Schedule fall inspection (ideal timing for many regions)
• Clean gutters and downspouts before winter
• Improve drainage around foundation
• Seal cracks in foundation before cold weather
• Remove dead vegetation and wood debris
• Store firewood away from house for winter
• Check attic ventilation before winter moisture buildup

Reduced Visible Activity

Why winter matters: Termites remain active but less visible. Good time for prevention and treatment in some cases.

What happens in winter:

• Subterranean termites: Move deeper underground (below frost line)
• Activity continues: Colonies remain active in protected areas
• Heated structures: Indoor infestations continue year-round
• No swarming: Reproductive flights cease until spring

Regional differences:

• Southern states: Activity barely slows; swarms possible in warm spells
• Mild climates: Year-round activity with little seasonal variation
• Northern states: Significant slowdown but not complete dormancy
• Heated buildings: Indoor colonies active regardless of outdoor temperature

Winter Action Items

• Good time for treatment (less disruption, termites concentrated)
• Indoor inspections still valuable
• Monitor heated areas (basements, crawl spaces)
• Control indoor humidity
• Fix any moisture issues before spring
• Plan spring prevention measures
• Review and update termite protection plan

Tropical/Subtropical (South Florida, Hawaii, South Texas)

Activity level: Year-round, minimal seasonal variation

• Swarms possible any time of year
• Highest termite pressure in U.S.
• Multiple species active simultaneously
• Formosan termites particularly aggressive
• Recommendation: Year-round vigilance; quarterly inspections

Warm Temperate (Southeast, Southwest, Southern California)

Activity level: High spring-fall, reduced but present in winter

• Clear spring swarming season
• Summer peak activity
• Mild winters allow continued activity
• Both subterranean and drywood species common
• Recommendation: Spring and fall inspections

Cool Temperate (Mid-Atlantic, Midwest, Pacific Northwest)

Activity level: Moderate spring-fall, low in winter

• Distinct spring swarming season
• Summer activity peak
• Fall slowdown
• Winter dormancy in outdoor colonies
• Primarily subterranean species
• Recommendation: Annual spring or fall inspection

Cold Temperate (Northern states)

Activity level: Short active season, significant winter dormancy

• Late spring to early fall activity
• Lower overall termite pressure
• Heated structures still vulnerable
• Primarily subterranean species
• Recommendation: Annual inspection, focus on heated areas

Conditions That Increase Activity

Temperature:

• Optimal: 75-95°F for most species
• Swarming triggered by warm days (70°F+)
• Activity slows below 50°F
• Freeze kills exposed termites but not protected colonies

Moisture:

• Rain increases subterranean termite activity
• High humidity favors all species
• Swarms often follow rain by 1-3 days
• Drought can drive termites toward structures seeking moisture

Barometric pressure:

• Swarms often occur before weather fronts
• Stable high pressure with warmth ideal for swarming