What to Do When Solar Output Drops in Winter vs Summer

Modified on Mon, 22 Sep at 11:58 PM

Why Solar Output Changes with the Seasons

Solar panels don’t produce the same amount of energy year-round. Seasonal factors such as sunlight hours, panel angle, temperature, and weather conditions all influence how much electricity your system generates.

In Australia, you’ll notice higher energy production in summer and lower production in winter — but the reasons go beyond just the length of the day.

Seasonal Factors That Affect Solar Performance

1. Daylight Hours

Summer: Longer days mean more sunlight hours, boosting daily energy production.
Winter: Shorter days = fewer sunlight hours, which reduces output.

2. Sun Angle

In summer, the sun is higher in the sky, meaning panels receive more direct light.
In winter, the sun sits lower, and panels may not capture light as effectively unless tilted appropriately.

3. Temperature

Solar panels are less efficient in extreme heat.
On very hot days, performance may dip by 5–10%.
Cooler winter temperatures actually improve panel efficiency, but shorter days and low sun angle still mean less overall energy.

4. Weather Conditions

Summer: Storms, haze, and humidity can reduce output.
Winter: Cloud cover, frost, or shading (e.g., low sun behind trees/buildings) can further reduce production.

How to Improve Solar Performance Year-Round

✅ Adjust Panel Tilt (if possible)

Tilting panels more upright in winter can help capture the lower sun.
A fixed tilt compromise (around your latitude) usually works best for year-round performance.

✅ Keep Panels Clean

Dust, leaves, and bird droppings reduce performance year-round.
In winter, clear off frost or debris that blocks sunlight.

✅ Manage Shading

Winter sun angles can introduce new shading issues (from trees, fences, or nearby buildings).
Trim vegetation and adjust placement where possible.

✅ Consider System Sizing

If you rely heavily on solar in winter, oversizing your array or adding extra panels ensures you still meet your needs during low-production months.

✅ Add Battery Storage

A solar battery allows you to store excess summer energy for use in evenings or cloudy days — and provides resilience in winter when generation is lower.

✅ Hybrid Systems for Backup

Adding a generator or hybrid inverter setup ensures you have reliable power even during extended cloudy periods.

What to Expect in Australia

Summer: Expect high production, but with some efficiency loss in extreme heat.
Winter: Production can drop by 30–50% compared to summer, depending on your location.
Best Months: Spring and autumn often deliver the most consistent balance of sunlight hours and mild temperatures.

Key Takeaways

Seasonal changes in solar output are normal and expected.
Output is highest in summer due to long days but can be reduced by heat.
Output is lowest in winter due to shorter days and lower sun angles, even though cooler temps improve efficiency.
Proactive steps like cleaning, adjusting tilt, adding batteries, or oversizing your array can help you make the most of your solar investment year-round.

✅ Pro Tip: If you notice a sudden or drastic drop in output (beyond normal seasonal variation), it may indicate a fault in your panels, inverter, or wiring. Check your monitoring system and contact a professional if needed.