The short answer
Winter production is lower for predictable reasons: shorter days, more cloud and snow, and a lower sun. Tesla says it is typical for a system to produce closer to 50% of its potential at noon in winter, versus up to 100% in summer. So the useful comparison is this winter against last winter, not against July.
Safe checks you can do now
- Compare winter with winter
Put this December next to last December in your app. Similar weather and similar totals mean the system is likely fine.
- Check a location-based estimate
PVWatts gives monthly production estimates for a location and system, which shows how much lower winter months are expected to be. Source: PVWatts calculator: location-based production estimates.
- Watch for snow that does not clear
Snow on panels stops production until it slides or melts. Do not climb on the roof or use metal tools on panels; ask your installer about safe snow removal if it lingers.
- Look for new winter shade
A low winter sun casts longer shadows. A tree or chimney that never shaded the array in summer can in December.
- Check for alerts
Cold weather does not normally cause errors. An alert in winter still needs the same attention as any other time.
Only do the checks on this page that need no tools: read the app, look at the inverter or gateway lights, reset a tripped breaker that is labelled for the solar system or gateway, and look at the array from the ground. Never open an electrical panel, inverter, combiner or junction box, never touch wiring or connectors, and never climb onto the roof. Solar equipment can stay energized while the sun is up even when the grid is off. If a breaker trips again, you smell burning, or you see scorch marks, water in equipment or damaged wiring, stop and call your installer or a licensed electrician.
When winter dips are a problem
It is worth a closer look if this winter is clearly lower than last winter in similar weather, if one part of the array produces much less than the rest on clear days, or if production stays at zero for days after snow has cleared. Try the underperformance check or request a free review below.
When to call your installer or an electrician
- Zero production for days after snow has cleared.
- This winter far below last winter in similar weather.
- Ice dams or roof leaks near the array.
- Any alert or visible damage.
If you are not sure, treat it as a job for a professional. Our free remote review can help you decide what to ask for, but it does not replace a licensed electrician or your installer.
Get a free remote review of your system
Tell us which monitoring app your system uses (Enphase, SolarEdge, Tesla, SMA, Fronius, Generac or another brand). We send you the steps to add our team as a viewer or installer from inside the provider’s own app. You never share your password with us. Once access is granted, our team connects your system and runs a free remote review of your production and alerts, then tells you what we found and the next step.
- 01Tell us your monitoring brand
- 02Grant viewer or installer access in your app
- 03Our team reviews it and reports back
Remote data can show when and where production changed, but it cannot always find the physical cause. Some issues need an on-site visit or your installer. We never ask for your monitoring password.
Prefer not to use the form? Start your free review here.
Questions homeowners ask
Is it normal for solar panels to produce less in winter?
Yes. Shorter days, more cloud and snow, and a lower sun angle reduce output. Tesla says winter production at noon is typically closer to 50% of a system’s potential, versus up to 100% in summer.
Should I remove snow from my solar panels?
Do not climb on the roof or scrape panels. Snow usually slides or melts off; if it lingers, ask your installer about safe options.
How do I know if low winter production is a problem?
Compare with the same month last year in similar weather, and with a location-based monthly estimate. A clear shortfall is worth a review.
Related guides
Sources
- Tesla Support: Understanding system performance
- PVWatts calculator: location-based production estimates
- U.S. DOE (FEMP): Operate and maintain an existing PV system
Brand-specific facts and error-code meanings come from the manufacturer’s own documentation, linked above, checked 2026-10-09. Manufacturers update their guidance; follow the current version for your equipment. Published by Solar Survey AI. Our safe-action advice is our own, not the manufacturer’s.