What it yields where you are
How much solar produces in Perugia
In Perugia a well-oriented system produces 1,368 kWh a year for every kWp installed. A 6 kW system — a home-sized one — makes about 8,206 kWh a year. The figures below come from PVGIS, the European Commission's database.
1,368
kWh a year for every kWp
8,206
kWh a year from a 6 kW system
36°
the best tilt, facing south
01At a glance
A year of sun in Perugia.
A 6 kW system produces
8,206 kWh
About what 4.1 households use in a year.
The best month
July
969 kWh: 2.7 times the worst month.
Hours of sunshine a year
3,522 h
9.6 hours a day on average. In the leanest month it drops to 6.0.
How cloudy the sky is
49%
Average over the year. The cloudiest month is January, at 63%.
Warmest month's temperature
24.4 °C
In the coldest month the average is 3.9 °C.
How much it changes year to year
from −5% to +5%
Sunlight measured over the last twenty years, against the average.
02System sizes
How much a system produces in Perugia
The three sizes people actually put on a house, on the best plane.
3 kW
4,103
Produces each year · kWh
450 W modules: 7
6 kW
8,206
Produces each year · kWh
450 W modules: 13
10 kW
13,676
Produces each year · kWh
450 W modules: 22
03Month by month
Month by month in Perugia
A yearly total doesn't say when the energy arrives, and that's the part that decides whether you need storage.
A 6 kW system yields most in July, with 969 kWh, and least in December, with 366: 2.7 times as much. That's why the summer bill goes to zero and the winter one doesn't.
| Month | Output of 6 kW | Sunshine | Cloud | Temperature | Days above 30°C |
|---|---|---|---|---|---|
| January | 407 kWh | 192 h | 63% | 3.9 °C | — |
| February | 492 kWh | 207 h | 58% | 5.6 °C | — |
| March | 704 kWh | 272 h | 56% | 7.6 °C | — |
| April | 795 kWh | 322 h | 52% | 11.0 °C | — |
| May | 853 kWh | 356 h | 56% | 15.4 °C | — |
| June | 893 kWh | 395 h | 38% | 20.7 °C | 7 |
| July | 969 kWh | 426 h | 22% | 24.4 °C | 19 |
| August | 925 kWh | 388 h | 27% | 23.8 °C | 17 |
| September | 772 kWh | 319 h | 44% | 18.5 °C | 1 |
| October | 629 kWh | 264 h | 54% | 14.1 °C | — |
| November | 404 kWh | 200 h | 63% | 9.1 °C | — |
| December | 366 kWh | 181 h | 59% | 5.2 °C | — |
Heat costs yield: above 25 °C of cell temperature a panel loses about 0.4% per degree, and in summer the cell runs some twenty degrees above the air. Here there are 44 days above 30 °C a year, nearly all between June and August. That loss is already inside the figures above — don't subtract it twice — but it is why July, which gets the most sun of any month, never yields as much as the extra sun would suggest.
Output: our own calculation on PVGIS irradiation, calibrated against PVGIS city by city and month by month. Sunshine, cloud, temperature and hot days: ten-year averages 2015-2024 from the ERA5 reanalysis, via Open-Meteo. Two different sources, in separate columns on purpose.
04Orientation
And if the roof doesn't face south
In Perugia the two sides are not equivalent, and it's worth knowing beforehand: compared with a south-facing roof you lose about 15% facing east and 25% facing west. The sun's geometry is symmetrical and this place is not — the terrain around counts, and here it sits on one side only, and so does the air, which is not the same in the morning as in the afternoon. On a roof facing the wrong way it costs as much as a smaller system.
South-facing, 30°
1,350 kWh/kWp
The benchmark
East-facing, 30°
1,144 kWh/kWp
−15% compared with south
West-facing, 30°
1,007 kWh/kWp
−25% compared with south
05The years
And if next year is cloudy?
Fair question: the sun isn't the same every year. Here is how much it actually varied, from 2005 to 2024.
Over twenty years the poorest was 2010: 5% below average. The most generous was 2022: 5% above. Every other year sits in between. That's why a solar estimate uses the average of many years and not the last one — a bad year doesn't change the maths of a system that lasts twenty-five.
Yearly irradiation from 2005 to 2024 according to the ERA5 reanalysis, via Open-Meteo, against its own average. This is a different database from the one behind the output figures above, which comes from PVGIS and stops at 2023 — which is why the two periods don't match.
06For designers
The technical figures
The ones a designer needs. If you don't know them, you don't need them: everything is above.
Yield per installed kW
1,368 kWh/kWp
How many kWh each kW of panels gives in a year, on the best possible roof.
Best tilt
36°
The angle worth using here, facing south.
Sunlight reaching the ground
1,550 kWh/m²
Solar energy landing on one flat square metre in a year.
Other cities
Your roof isn't an average.
These figures are for an ideal roof in Perugia. The estimate on your address accounts for your roof, the shade and your consumption: two minutes, without leaving your contact details.