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Autumn: The Transition Season for Solar
Autumn (September–November) is a transition period for solar panel generation in Ireland. The season starts with strong summer-like output in September and ends with winter-level generation by November. Understanding this transition helps you manage your expectations and make the most of your system's output during these months.
September: Still Strong
September is often one of the most pleasant months for solar generation. While days are shortening, temperatures are mild (which helps panel efficiency) and the sun angle is still relatively high. A 4kW system typically generates 230–320 kWh in September — roughly 60–70% of peak summer output. Many September days can still produce 12–15 kWh from a 4kW system, making it an excellent month for solar.
October: Noticeable Decline
By October, the reduction in daylight hours becomes more apparent. A 4kW system generates approximately 150–220 kWh during the month. Daily output drops to an average of 5–7 kWh, though clear October days can still achieve 10+ kWh. This is the month when solar homeowners notice their monitoring apps showing lower daily figures, and it's a good time to review your consumption habits ahead of winter.
November: Approaching Winter
November sees generation approach winter levels. A 4kW system typically produces 70–120 kWh during the month, with daily averages of 2–4 kWh. The weather also tends to be more overcast and stormy in November, which further reduces output. However, even at these lower levels, November generation saves €25–€50 on your electricity bill.
Autumn Preparation Tips
Autumn is the ideal time to prepare for winter:
- Check panel cleanliness: Autumn leaves and debris can accumulate on roof-mounted panels. A quick visual check (or review of your monitoring data) can identify any performance issues.
- Review your tariff: Many energy suppliers adjust tariffs in October/November. Compare your current deal against the market to ensure you're on the best rate for winter.
- Service your battery: If you have battery storage, autumn is a good time to check its health and ensure it's optimised for winter operation.
- Plan consumption shifts: As generation declines, maximise the value of what you produce by shifting heavy appliance use to the brightest part of the day (typically late morning).
Frequently Asked Questions
How much do solar panels generate in October?
A 4kW system generates approximately 150–220 kWh in October, with daily averages of 5–7 kWh.
Do solar panels work during autumn storms?
Solar panels are designed to withstand extreme weather, including Irish autumn storms. While output is lower during overcast conditions, the panels remain safe and continue to generate some electricity.
Should I clean my solar panels in autumn?
Yes. Autumn leaves and debris can accumulate on panels. A visual check and cleaning if needed can help maintain optimal performance through the winter months.