Bug bites in California — what bit you?
16 biting or stinging species have verified records in California. The local season runs March to November in this mediterranean to arid climate. Narrow yours down below, then confirm it with a photo in the app.
This page tells you what's around in California. The app tells you what bit you — photo in, likely species, severity read and a day-by-day care plan out.
Download free for iPhoneNarrow it down in three taps
Free · nothing to install to get a shortlistMost recorded in September
Answer 2 more for a sharper shortlist-
Bald-faced hornet sting Strongest match · 92%Often several — the colony defends aggressively. Usually swelling for several days.
Read the full profile → - Chigger bite Also possible · 88%
Clusters concentrated where clothing is tight. Usually 1 to 2 weeks of itch.
Read the full profile → -
Mosquito bite Also possible · 49%Single bumps scattered over exposed skin. Usually 1 to 3 days, sometimes a week in children.
Read the full profile →
Photograph the bite in the app and it picks between these for you — with a severity read and what to do today. This page narrows the field; it does not diagnose you.
Confirm with a photoFree download · iPhone The year, month by month
Share of all recorded sightings in California. Pick a month to re-run the shortlist above for that time of year.
From GBIF biodiversity records, snapshot 2026-09-14. Records track when people observe and report specimens — close to activity, not identical to how often anyone gets bitten. Methodology.
Recorded biting species in California
Record counts come from GBIF and reflect how often a species is reported and identified in California. A guide to what is plausible here, not a census.
Narrowing it down in three questions
- Where on your body? Below the knee in clusters points to fleas or chiggers. Uncovered skin — arms, shoulders, neck — points to bed bugs or mosquitoes. Along a sock line or waistband is close to diagnostic for chiggers.
- How are they arranged? A line or zigzag of three or more suggests bed bugs. Scattered single bumps suggest mosquitoes. A curved group with white pustules the next day means fire ants.
- Indoors or outdoors, and when? In California the outdoor season runs March to November; the indoor species run all year — see what is biting me at night.
- Breathing trouble, or swelling of the lips, tongue or throat after a sting
- A red area that is spreading, hot and painful — especially with a red streak
- Fever, chills or feeling generally unwell in the days or weeks after a bite
- An expanding rash appearing 3 to 30 days after a tick bite
- A bite getting worse rather than better after 72 hours
Short of urgent: urgent care or your own provider. Poison Control 1-800-222-1222 handles spider and scorpion questions.
Bite season month by month
Of the 16 species recorded in California, 16 are active in June — the peak of the local season. The mediterranean to arid climate here is what sets those boundaries: species that need warmth disappear at the edges of the year, while the indoor ones do not care. By sighting records the busiest month here is April, at 16% of the year's total.
| Month | Species active | Notably |
|---|---|---|
| January | 3 | Bed bug, Head lice bites, Scabies |
| February | 3 | Bed bug, Head lice bites, Scabies |
| March | 7 | Honey bee, Fire ant, Bed bug |
| April | 12 | Honey bee, American dog tick, Yellow sac spider |
| May | 14 | Honey bee, Paper wasp, American dog tick |
| June | 16 | Honey bee, Paper wasp, American dog tick |
| July | 16 | Honey bee, Paper wasp, American dog tick |
| August | 16 | Honey bee, Paper wasp, American dog tick |
| September | 15 | Honey bee, Paper wasp, Bald-faced hornet |
| October | 13 | Honey bee, Bald-faced hornet, Yellow sac spider |
| November | 6 | Yellow sac spider, Fire ant, Bed bug |
| December | 3 | Bed bug, Head lice bites, Scabies |
Stings rather than bites in California
Honey bee, Paper wasp, Bald-faced hornet, Fire ant, Yellowjacket, Carpenter ant are recorded here. Stings differ from bites in one way that matters: they can cause anaphylaxis in sensitised people, and that risk does not depend on how bad previous stings looked. Anyone who has had a severe reaction should carry an adrenaline auto-injector.
Species associated with illness here
- American dog tick bite — Rocky Mountain spotted fever, tularemia, tick paralysis (rare, resolves on removal)
- Mosquito bite — West Nile virus, La Crosse encephalitis, dengue (Gulf Coast and Southwest, local cases), chikungunya (rare, travel-linked)
- Flea bite — murine typhus (Gulf Coast, California, Hawaii), cat scratch disease bacteria carried between cats, flea tapeworm (mainly in children who swallow a flea)
- Scabies rash — secondary bacterial skin infection is common from scratching
- Kissing bug bite — Chagas disease (Trypanosoma cruzi) — rare in the United States but the reason this bite is taken seriously
Most bites from these species transmit nothing. What matters is the follow-up: note the date of the bite, and report any fever or expanding rash in the following weeks to a clinician, mentioning the bite explicitly.
Year-round in California
Weather does not affect everything. Bed bugs, scabies and head lice depend on people rather than season, so a bite pattern in January in California points to those first.
Common questions
What bites are most common in California?
By verified sighting records, the most frequently recorded biting species in California are honey bee, paper wasp, american dog tick, bald-faced hornet, yellow sac spider.
When is bite season in California?
Broadly March to November, driven by the mediterranean to arid climate. Bed bugs, scabies and head lice are year-round because they do not depend on weather.
Something bit me at night in California — what was it?
Overnight bites most often mean bed bugs, fleas or mosquitoes. Lines of welts on uncovered skin suggest bed bugs; clusters below the knee suggest fleas.
Stop guessing from a table.
One photo → likely species, severity, and a care plan you can re-check as it heals.