Anyone else notice their panels putting out more in February than they expected?

Been genuinely surprised this past week or two. My cabin setup has a pair of 200W Renogy panels on a south-facing roof, and the Victron MPPT is logging some decent numbers — way better than I'd mentally budgeted for heading into February.

I think people (myself included) tend to write off winter as a dead loss and just focus on battery capacity to get through it. But the combination of low sun angle plus cold clear days seems to be doing something useful. Panels love the cold, don't they — better efficiency than baking in July apparently.

Had a couple of days last week where I was actually hitting close to rated output in the early afternoon. That genuinely caught me off guard.

A few things I'm wondering about and curious whether others have noticed:

• Is it just the cold temps boosting efficiency, or is the cleaner winter air also a factor?
• Does anyone track their monthly yield properly? I've been a bit inconsistent with logging
• Those of you with east/west splits rather than pure south — are you seeing the same, or does the low sun angle hurt you more?

I've also got a small garden office setup I'm planning to expand this spring, so trying to work out whether my winter assumptions have been too pessimistic all along. Might mean I don't need as much battery storage as I thought, which would be handy given what Fogstar cells are going for at the moment.

Would be interested to hear what others are seeing across different parts of the UK — imagine it varies a fair bit between south coast and further north.

@CliffWill — same story here with the tiny house. February catches people out every year because nobody accounts for the low sun angle actually working in your favour on a pitched roof, combined with that crisp cold air keeping panel temps down (efficiency goes up as panels cool).

Had a cracking afternoon last Tuesday where my Fogstar-fed bank was sitting full by 2pm — almost unheard of in December.

The other thing worth watching: snow on the ground acts like a giant reflector. Had a dusting last week and the Victron logs showed a noticeable spike right after it settled. Bifacial panels would've made even more of that.

Managed a decent chunk of EV charging off solar in February which felt almost wrong given the month. Don't knock it though — bank it while it's there.

Really interesting to see this across different setups. Is anyone else finding the angle makes a significant difference this time of year?

My shepherds hut panels are at a fairly shallow pitch and I'm wondering whether I'd get noticeably better numbers if I tilted them steeper for winter/spring — the sun's still pretty low even now.

Also curious what @CliffWill is seeing in terms of panel temperature — I've read that cold clear days can actually push output above rated wattage because silicon performs better when it's not cooking. Does the Victron app show anything useful there, or would I need a separate sensor to confirm it?

@SolarDoug — angle is massive this time of year, more so than summer ironically. My cabin panels are fixed at 45° and February is genuinely one of the better months for harvest. The sun sits lower so a steeper tilt intercepts the beam radiation far more directly than in June when you'd want something shallower.

What catches most people out is the cold clear sky effect — panel efficiency climbs noticeably when ambient temps drop. My Fogstar 280Ah lithium bank has been staying topped up far earlier in the afternoon than I'd expect. The Victron MPPT data backs it up; Voc is noticeably higher on a crisp February morning versus a warm July one.

The real enemy is still day length obviously, but if your geometry is right and you get a clear spell, February can genuinely outperform months that feel "sunnier."

Great thread — I've been noticing exactly the same thing on my Kangoo van setup this past fortnight. What catches most people out, I reckon, is the combination of low sun angle reflecting off snow or frost on the ground and the genuinely cold temperatures keeping panel efficiency up. Panels actually perform better in the cold — they're rated at 25°C and anything below that gives you a bonus. February sunshine might feel weak but it's surprisingly effective when the air is crisp. @WezWhite72 is spot on about the angle too — worth anyone with adjustable mounts bumping theirs up a notch right now if you can. I'd also suggest logging your peak output times — I've found my best generation window has shifted noticeably later compared to December, which always feels like a proper milestone!

@WezWhite72 makes a good point about angle — I've been thinking the same on my motorhome. Fixed panels are obviously a compromise, but I'm curious whether anyone's actually done the maths on how much you'd gain at this latitude by adjusting tilt seasonally vs just leaving them set?

I run a pair of 175W panels on the roof (flat-ish, maybe 8° due to the roofline) and even so I've been genuinely surprised by the Victron logs this past week. Cold clear days seem to push efficiency noticeably compared to the summer heat.

One thing I haven't seen mentioned — has anyone cross-referenced their output spikes with the Met Office UV index data? I've been wondering whether irradiance figures would help predict good days better than just checking for sun icons on a weather app.