Solar Panel Installer St Helens (solar for St Helens homes) / Shade
Winter sun in St Helens: how low it gets, and what that means for panels
Shade is a winter problem because the sun is low. In St Helens the midday sun climbs to about 60 degrees in June but only about 13 in December, when a garden fence casts a shadow four times its height. Here is the year, month by month.
Sources read on 3 November 2026. Published by SEO Dons, which runs this St Helens site.
The year in one table
| Month | Midday sun height | Shadow of a 1 m object | Hours of sun above the horizon | kWh per kW (south, 35°) | Share of the year |
|---|---|---|---|---|---|
| January | 16° | 3.4 m | 8.0 | 30 | 3.2% |
| February | 26° | 2.1 m | 10.0 | 49 | 5.3% |
| March | 36° | 1.4 m | 12.0 | 82 | 8.8% |
| April | 48° | 0.9 m | 14.1 | 110 | 11.7% |
| May | 57° | 0.7 m | 15.9 | 122 | 13.0% |
| June | 60° | 0.6 m | 16.8 | 117 | 12.4% |
| July | 57° | 0.6 m | 16.1 | 116 | 12.3% |
| August | 49° | 0.9 m | 14.3 | 104 | 11.1% |
| September | 38° | 1.3 m | 12.2 | 85 | 9.1% |
| October | 26° | 2.0 m | 10.1 | 57 | 6.1% |
| November | 17° | 3.3 m | 8.1 | 38 | 4.1% |
| December | 13° | 4.3 m | 7.2 | 27 | 2.9% |
Sun height, shadow and day length: our calculation from the NOAA solar equations for St Helens. Output: PVGIS 5.3 for central St Helens, 14% losses, average month (not the 21st). Read on 3 November 2026.
Long shadows, little to lose
In midwinter the sun stays in the southern sky and never rises far, so anything to the south throws a long shadow: about 4.3 m for every metre of height at midday on 21 December, longer in the morning and afternoon. A two-storey house across a terraced street can shade a whole south-facing roof for most of a December day.
The same months bring little energy anyway. December's 27 kWh per kW is about 2.9% of the year, against 12.4% in June. Sunlight is weaker when it passes through more atmosphere, days are short and skies cloudier. So an obstacle that only shades panels from November to January usually costs a few per cent of the year, not a third.
Three dark months in kilowatt-hours
For a 3.5 kW south-facing system in central St Helens, November, December and January together bring about 334 kWh, by PVGIS's averages. A household using Ofgem's medium 2,500 kWh a year gets through that much in about 49 days. So winter is not when panels earn their keep, and it is not worth paying much, in money or in roof space, to rescue output that a winter shadow takes away.
Deciding about a winter-only shadow
If the shade checker shows an obstacle reaching the panels only from November to January, the sensible course is usually to accept it and fit the panels anyway. If it also reaches them in October and February, ask the installer whether optimisers on the affected panels would recover enough to justify their cost; if it reaches them in spring, that is a different conversation, about moving the panels or not fitting them there at all.
The shoulder months matter more
March, April, September and October are where shade starts to cost real output: the sun is still fairly low, but the months bring useful energy. An obstacle that shades the panels at midday in March and September, when the sun is around 36 to 38 degrees high, is worth designing around. The shade checker shows exactly which months a given obstacle reaches.
Summer evenings and mornings
In June the sun rises in the north-east and sets in the north-west, so an east or west roof gets early and late sun that a south roof misses, and obstacles to the north-east or north-west can matter in summer. If your panels face east or west, check obstacles in those directions too.
Related pages
References
Questions about winter sun
Do solar panels work in winter in St Helens?
Yes, but they make much less. PVGIS gives a south roof at 35 degrees here about 27 kWh per kW in December against 117 in June. November to January together make about 10% of the year.
How long are shadows in winter?
At midday on 21 December the sun is about 13 degrees up, so a 1 m object casts a shadow about 4.3 m long. In June it is about 0.6 m.
Should I worry about winter shade?
Less than summer shade. Because so little of the year's output comes in the darkest months, an obstacle that only shades the panels from November to January costs little over a year, even though it may shade them for much of each day then.
Get a solar quote for your St Helens roof, shade and all
Tell us what you would like a quote for, with your St Helens postcode and what stands to the south of the roof: a stack, the houses opposite or a tree. Your details go to SEO-DONS LTD, publisher of Solar Panel Installer St Helens, and we reply by email.
What happens next
- Send the form: it reaches SEO-DONS LTD, and a full postcode tells us which part of the borough you are in.
- We read it and reply by email, with the figures and sources that apply to you.
- Asking for a quote costs nothing, and whether and with whom you go ahead is your decision.