A fast, honest answer to whether mosquitoes are active where you are — built on real weather data and a two-signal model that separates population pressure from day-to-day biting conditions.
Most mosquito trackers collapse everything into a single weather reading. That produces an unstable number that jumps around whenever a cloud passes. The model here separates two distinct things that drive mosquito activity, because they operate on completely different timescales.
The first signal is population pressure — how many adult mosquitoes are likely out there right now. This is a slow-moving structural factor driven by whether conditions over the past one to two weeks allowed eggs to hatch and larvae to mature. It changes over days and weeks, not hours.
The second signal is current activity conditions — whether the existing mosquito population is flying and biting today. This is the fast-moving layer: temperature, humidity, and wind determine whether adults are active right now.
The displayed activity level combines both. A high population pressure score with poor current conditions (cold snap, high wind) will show lower activity than the same population on a warm, still, humid evening.
Mosquito eggs require standing water to hatch, and larvae take 4–7 days to develop into adults under typical warm conditions. This means rainfall from one to two weeks ago is the primary driver of how many adults exist today, not rainfall right now.
The model checks whether at least half an inch of rain fell in the 7–14 day window before today. If it did, it then checks whether conditions in the days following that rain would have allowed standing water to persist long enough for larvae to mature. If the post-rain period was dominated by temperatures above 90°F with no refill rain — as commonly happens in the South and Southwest — small containers and puddles evaporate before larvae can complete development, and the breeding signal is cancelled. Rain that falls and then gets baked off the same week doesn't produce a new generation.
The seasonal window — the weeks of the year when mosquitoes are typically active in your region — also factors into the structural score. A 75°F day in January in Minnesota gets a different read than the same conditions in July.
Given the existing population, whether mosquitoes are actively biting depends on three current conditions pulled from real-time weather data.
Temperature is the primary gate. Most US species become active above 50°F. Activity increases through the 60s and peaks between 70–90°F. Heat suppression sets in above 90°F as adults seek shelter; above 94°F activity drops significantly. The model rounds temperature to the nearest degree before applying tier thresholds — sub-degree fluctuations in the API response don't change the output.
Humidity amplifies or dampens activity. Readings at or above 80% add one level; very dry air below 33% subtracts one. Thresholds are set with a margin on purpose — hovering at 78% vs. 79% shouldn't produce a different answer on page reload.
Wind is a natural suppressant. Mosquitoes are weak fliers. Sustained winds above 20 mph make biting difficult and reduce pressure by one level.
Active rain is no longer used as a modifier in the current-conditions signal. Light rain doesn't meaningfully suppress adult activity — mosquitoes fly in drizzle — and instantaneous precipitation readings are noisy enough to cause spurious level changes. Rain's effect on the model is captured in the population pressure signal (via the breeding lag), where it actually matters.
The model outputs a level from 0 to 5. Level 2 and above is considered "season" — the threshold where biting pressure is meaningful enough to prompt precautions for most people.
Weather data comes from Open-Meteo, an open-source weather API that aggregates forecasts from NOAA, ECMWF, and other global models. It provides current conditions, hourly forecasts, and 14 days of historical daily data — all at no cost and with no user tracking. Calls are made directly from your browser; nothing passes through our servers.
West Nile virus data comes from CDC ArboNET via the CDC's open data API. The banner on the home page shows confirmed case counts for your state in the current year, updated as CDC publishes new weekly data. It fails silently if the endpoint is unreachable — the banner simply stays hidden.
Location is obtained via your browser's Geolocation API and used only to fetch weather data for your coordinates. It is never stored, logged, transmitted to our servers, or shared with third parties. Reverse geocoding (converting coordinates to a city and state name) is handled by Nominatim, which is also queried directly from your browser.
Species biology, disease risk context, and entomological thresholds are drawn from CDC Mosquitoes, the American Mosquito Control Association, and published entomological literature. Nothing on this site is medical advice.
This site is part of a small network of seasonal condition trackers built to give people fast, honest answers about what's actually happening outside — without paywalls or the noise that comes from sites trying to maximize time-on-page. Sister sites cover allergy season at isitallergyseasonyet.com and flu season at isitfluseasonyet.com.
If something looks wrong, a threshold seems off for your region, or you have a question about how the model works, the contact page goes directly to the person who built it.
Some product links — particularly repellent and yard-control recommendations in the activity section and guides — are affiliate links. If you purchase through one of these links, we may earn a small commission at no additional cost to you. Products are selected based on documented effectiveness and EPA registration, not compensation.