Window screens
Mosquito season in Reno-Sparks: why window screens matter
Northern Nevada Public Health treats May through September as mosquito season, and in 2024 it found mosquitoes carrying West Nile virus in ZIP codes 89436 and 89521, advising residents to install "protective screens on doors and windows." Intact, tight-fitting screens let you open the house on cool summer nights while keeping mosquitoes outside, and you can check yours for tears and gaps in a few minutes.
Updated · A-Affordable Screen, Sparks
What local health officials found
On Aug. 27, 2024, Northern Nevada Public Health (NNPH, formerly the Washoe County Health District) announced that mosquito samples from two ZIP codes had tested positive for West Nile virus: 89436, which covers Spanish Springs and north Sparks, and 89521 in South Reno. The same release said, "No human cases of the virus have been reported in Washoe County."
Among its prevention steps, NNPH listed wearing loose-fitting long sleeves and pants, using insect repellent, removing standing water near homes, and "installing protective screens on doors and windows." It also noted that mosquitoes are most active during morning and evening hours.
What each agency has said about screens
The advice has been consistent for years, from the county health district and from the CDC. Here it is side by side, with dates.
| Agency | Date | What it said |
|---|---|---|
| Northern Nevada Public Health | Aug. 27, 2024 | Prevention includes "installing protective screens on doors and windows"; mosquitoes most active morning and evening. |
| Northern Nevada Public Health memo to Reno City Council | May 15, 2025 | Mosquito season runs May through September; targeted treatment by drone or by hand; direct mosquito complaints to 311. |
| Washoe County Health District | Sept. 15, 2015 | "Make sure that your doors and windows have tight-fitting screens to keep mosquitos out. Repair or replace screens with tears or holes." |
| CDC | Current guidance | "Use screens on windows and doors. Repair holes in screens to keep mosquitoes outdoors." |
Quotes are copied from each agency's own page or memo; links are in the sources list below.
When the season runs
In a May 15, 2025 memo to the Reno City Council, NNPH described the mosquito season as May through September. For 2025 it suspended large-area treatment and said, "Specific and targeted treatments will continue via drone or manual application," along with trapping and testing of mosquito samples. The memo asks residents to direct mosquito complaints to 311.
That county work goes after breeding sites and known problem areas. Screens are the at-home layer: they deal with the mosquitoes that still find their way to your house. The same memo's prevention tips for residents were to eliminate standing water, reduce lighting around the home during dawn and dusk, and use repellent and long sleeves outdoors.
This is not new advice here
The Washoe County Health District gave the same guidance a decade ago. On Sept. 15, 2015, reporting four human West Nile cases in southern Washoe County that season, it told residents: "Make sure that your doors and windows have tight-fitting screens to keep mosquitos out. Repair or replace screens with tears or holes."
The CDC's national guidance on preventing mosquito bites says the same in fewer words: "Use screens on windows and doors. Repair holes in screens to keep mosquitoes outdoors." The words "tight-fitting" and "repair" are the part that matters for most homes. A screen that is in the window but torn, loose or gapped around the frame is not doing the job the agencies describe.
Why screens get so much use in a Reno summer
Reno's dry air cools off fast after sunset. NOAA's 1991-2020 climate normals for Reno-Tahoe International Airport show a gap of about 33 degrees between the average summer high and low, so a July day near 94 degrees usually drops to around 60 overnight. Many households open the windows in the evening and early morning to let that cool air in.
Those are the same hours NNPH says mosquitoes are most active. An open window with a sound screen gets you the cool air; an open window with a torn screen, or no screen, invites mosquitoes in along with it. Our Reno sun, heat and wind data page has the full set of local climate figures.
| Month | Average high | Average low | Day-night range | Days at 90F or hotter |
|---|---|---|---|---|
| May | 74.1F | 46.6F | 27.5F | 1.5 |
| June | 84.6F | 53.8F | 30.8F | 10.2 |
| July | 93.9F | 60.4F | 33.4F | 23.9 |
| August | 92.1F | 58.1F | 34.0F | 21.8 |
| September | 83.8F | 50.3F | 33.5F | 7.5 |
Source: NOAA NCEI U.S. Climate Normals 1991-2020, Reno-Tahoe International Airport. The large range is why windows open at night.
Choosing mesh
The agencies' advice is about screens being in place, tight-fitting and free of holes, not about a special product. If you are replacing mesh anyway, it is worth thinking about what else the screen has to handle. A window a cat climbs may need heavier pet-resistant mesh, and a sunny west window may be a candidate for solar screens, a separate product.
Our screen mesh types guide compares the common options, and we bring samples to the free measure so you can see them against your windows.
Where screens usually fail
When a screen stops keeping insects out, it is usually for one of a few reasons: a tear or puncture in the mesh, mesh that has pulled loose from the spline along one edge, a frame that is bent or cracked so it no longer sits tight in its channel, or a window that has no screen at all. On sliding screen doors, the common gaps are at the latch side, where the door no longer meets the frame, and along the top and bottom where the door has started to sag.
Reno's sun and wind speed this up. The south and west sides of a house tend to show brittle, faded mesh first, and afternoon gusts pop screens out of windows and knock doors off their tracks. Our guide to Reno's afternoon wind and your screens covers the wind side.
A 10-minute screen check
- Look at each screen against the light for holes, tears and slits, including along the edges.
- Run a finger along the spline groove; mesh that has pulled out of it leaves a gap.
- Check that each screen sits fully in its channel with no daylight showing around the frame.
- Press on the corners; a loose or cracked corner can open a gap when the frame flexes.
- Slide the patio screen door closed and look for gaps at the latch side and the top track.
- Count your windows. A window you open often with no screen is the easiest place to start.
- Check low windows and the slider for pet damage near the bottom.
Patch, rescreen or replace
A small hole can be patched for the season. A screen with several tears, brittle mesh or loose spline is better rescreened, which means new mesh rolled into the existing frame, with new spline or the same spline reused if it is still good. A frame that is bent, cracked or missing needs a new screen built to the window. Our rescreen or replace guide walks through how to tell, and DIY vs pro rescreening covers doing it yourself.
| What you find | Usual fix | Where to start |
|---|---|---|
| One small hole | Patch for the season | Do it yourself |
| Several tears, brittle or loose mesh | Rescreen the frame | Screen repair and rescreening |
| Bent, cracked or missing frame | New screen built to the window | Custom window screens |
| Slider gaps, drags or jumps the track | Rescreen a sound frame, or a custom new door | Sliding screen doors |
The rest of the at-home list
Screens work best alongside the other steps the agencies list. The CDC says to check for water-holding containers around the house and, "Once a week, empty and scrub, turn over, cover, or throw out items that hold water, such as tires, buckets, toys, pools, birdbaths, flowerpot saucers, or trash containers." NNPH's 2025 tips add eliminating standing water and reducing lighting around the home during dawn and dusk. For anything about symptoms or health, follow NNPH and your doctor.
Getting screens ready before May
Spring is the easy time to fix screens, before the evenings warm up and the windows start staying open. A-Affordable Screen rescreens torn screens in their existing frames, builds new frames where the old ones are bent or missing, and rescreens or builds custom new sliding screen doors across Reno-Sparks, including Spanish Springs and South Reno. Call or text (775) 240-0418 for a free on-site measure and quote. Multi-window discounts apply.
Questions
Straight answers
Do window screens keep mosquitoes out?
That is what local and national health agencies use them for. NNPH advises "installing protective screens on doors and windows," and the Washoe County Health District's wording is "tight-fitting screens" with tears and holes repaired or replaced.
When is mosquito season in Reno and Sparks?
NNPH describes it as May through September. It says mosquitoes are most active in the morning and evening.
Where was West Nile virus found locally?
In 2024 NNPH reported positive mosquito samples in ZIP codes 89436 (Spanish Springs and north Sparks) and 89521 (South Reno), with no human cases reported in Washoe County at that time.
Who do I call about a mosquito problem in my neighborhood?
NNPH's 2025 memo asks residents to direct mosquito complaints to 311.
Do I need a special mosquito mesh?
The agencies' advice is about screens being whole and tight-fitting. If you are replacing mesh anyway, our mesh types guide compares the options.
Should I patch a small hole or rescreen?
A patch can close a small hole for the season. A screen with several tears, brittle mesh or loose spline is better rescreened.
What about my sliding screen door?
Check it the same way: holes in the mesh, gaps at the latch side, and a door that sags or jumps the track. If the frame is good, we rescreen it; otherwise we build a custom new sliding screen door measured to the opening.
Related
Keep reading
Sources: Northern Nevada Public Health: NNPH detects West Nile Virus in mosquitos in Northern Nevada (Aug. 27, 2024) (opens in a new tab) · Northern Nevada Public Health memo, Mosquito Abatement for 2025 season (May 15, 2025), via City of Reno (opens in a new tab) · Washoe County Health District: West Nile virus still present in Washoe County (Sept. 15, 2015) (opens in a new tab) · CDC: Preventing Mosquito Bites (opens in a new tab)
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