Dated, weather-based
Tomorrow's forecast
Tomorrow's value is a weather-based estimate for Tuesday, September 1, 2026: 21.0 kWh from the 10 kWp reference system, with a likely range of 12.8 kWh–29.0 kWh. It changes with the next weather forecast.
United Kingdom · 10 kWp reference system
Belfast solar forecast and PV yield
Photo: Florent Abel,CC BY-SA 4.0. Cropped, resized and converted to WebP by GridPassport.
Forecast target: . Any “tomorrow” label on this page refers to this dated target.
- Tomorrow's forecast
- 21.0 kWh 10 kWp reference system
- Typical annual output
- 9,188 kWh 10 kWp reference system
- Typical specific yield
- 919 kWh/kWp Per year
Tuesday, September 1, 2026
About 21.0 kWh tomorrow
For a standard 10 kWp south-facing system in Belfast, GridPassport estimates 21.0 kWh on Tuesday, September 1, 2026, with a likely range of 12.8-29.0 kWh. The strongest production window is expected at 10:00-14:00 local time.
Updated Aug 31, 2026, 12:01 AM GMT+1 · fresh snapshot- Likely range
- 12.8-29.0 kWh
- Strongest window
- 10:00-14:00
- Confidence
- medium
How to read and use the data
Belfast solar forecast: daily weather versus long-term PV yield
The daily and annual figures answer different questions. Use the dated forecast to plan tomorrow, and the PVGIS specific yield to compare locations or estimate a typical year.
Multi-year climate baseline
PVGIS specific yield
Belfast's PVGIS specific yield is about 919 kWh/kWp per year. It is a multi-year climate benchmark, not a prediction for tomorrow or for this calendar year. In the PVGIS profile, May is typically the strongest month and December the weakest.
3, 5 and 10 kWp reference systems
Scale the same assumptions to your system size
SystemTomorrow estimate (likely range)PVGIS typical year
3 kWpTomorrow estimate (likely range)6.3 kWh3.8 kWh–8.7 kWhPVGIS typical year2,756 kWh/year
5 kWpTomorrow estimate (likely range)10.5 kWh6.4 kWh–14.5 kWhPVGIS typical year4,594 kWh/year
10 kWpTomorrow estimate (likely range)21.0 kWh12.8 kWh–29.0 kWhPVGIS typical year9,188 kWh/year
Linear reference scaling only: south-facing, 35° tilt and 14% system losses. It does not resize inverter clipping, shade or local roof constraints.
From forecast to a household plan
Battery, EV, heat pump and flexible loads
Treat the forecast as a gross solar-energy budget before household base load and conversion losses. The numbers support scheduling; they do not guarantee surplus.
Battery
Keep room for the solar window
Use 10:00-14:00 as the first candidate charging window. Battery state of charge, reserve settings and inverter limits still decide how much can be stored.
EV
Compare the charge with the 5 kWp budget
The scaled 5 kWp estimate is 10.5 kWh before household use. Compare the remainder after base load with the planned EV charge and stagger charging if needed.
Heat pump
Shift only flexible thermal demand
If comfort controls allow it, place discretionary hot-water heating or pre-heating inside 10:00-14:00. Never override frost protection, hygiene cycles or manufacturer limits.
Large loads
Avoid stacking appliances
A 3 kWp system scales to about 6.3 kWh for the day before household use. Run flexible loads sequentially during the strongest hours rather than assuming all forecast energy is simultaneous power.
Local questions
Solar forecast FAQ
How much could a 5 kWp solar system produce tomorrow in Belfast?
Using the same south-facing, 35-degree and 14% loss assumptions, the 5 kWp estimate is 10.5 kWh for Tuesday, September 1, 2026, with a scaled likely range of 6.4 kWh–14.5 kWh. This is a linear reference-system estimate, not a site survey.
What does 919 kWh/kWp mean for Belfast?
It means the PVGIS multi-year profile produces about 919 kWh in a typical year for each installed kWp under the reference assumptions. A 5 kWp system therefore scales to about 4,594 kWh in a typical year before site-specific adjustments.
Is the Belfast forecast the same as the PVGIS annual estimate?
No. Tomorrow's forecast uses dated weather and an uncertainty band for one day. The PVGIS figure is a multi-year climate-based specific yield used for typical monthly and annual comparisons.
When should a battery, EV or heat pump use solar in Belfast?
Start with 10:00-14:00, then check household base load, battery headroom, EV energy required and heat-pump safety or comfort constraints. The forecast estimates daily energy, not guaranteed instantaneous surplus.
Typical year
Solar production month by month in Belfast
A standard 10 kWp system produces about 9,188 kWh in a typical year at this location. Monthly averages show seasonality; they are not a forecast for a specific year.
296Jan
474Feb
806Mar
1081Apr
1224May
1162Jun
1100Jul
1006Aug
813Sep
581Oct
381Nov
263Dec
Values are kWh per month. Source: European Commission JRC PVGIS.
What makes Belfast's solar profile different?The typical annual yield is about 919 kWh per installed kWp, ranking Belfast #9 of 12 modelled locations in United Kingdom. That is 3% below the median of the 12 United Kingdom locations in this dataset. May is typically the strongest month and December the weakest; the stronger month produces about 4.6 times as much.
See the 12-month data
MonthMonthly outputDaily averageYear-to-year variation
MonthJanuaryMonthly output296 kWhDaily average9.5 kWh/dayYear-to-year variation±48 kWh
MonthFebruaryMonthly output474 kWhDaily average16.9 kWh/dayYear-to-year variation±75 kWh
MonthMarchMonthly output806 kWhDaily average26.0 kWh/dayYear-to-year variation±128 kWh
MonthAprilMonthly output1,081 kWhDaily average36.0 kWh/dayYear-to-year variation±149 kWh
MonthMayMonthly output1,224 kWhDaily average39.5 kWh/dayYear-to-year variation±106 kWh
MonthJuneMonthly output1,162 kWhDaily average38.7 kWh/dayYear-to-year variation±134 kWh
MonthJulyMonthly output1,100 kWhDaily average35.5 kWh/dayYear-to-year variation±105 kWh
MonthAugustMonthly output1,006 kWhDaily average32.5 kWh/dayYear-to-year variation±89 kWh
MonthSeptemberMonthly output813 kWhDaily average27.1 kWh/dayYear-to-year variation±69 kWh
MonthOctoberMonthly output581 kWhDaily average18.7 kWh/dayYear-to-year variation±67 kWh
MonthNovemberMonthly output381 kWhDaily average12.7 kWh/dayYear-to-year variation±63 kWh
MonthDecemberMonthly output263 kWhDaily average8.5 kWh/dayYear-to-year variation±49 kWh
Nearby solar forecasts
Compare Belfast with nearby cities
Tomorrow, in one email
Get Belfast's solar forecast by email
Tomorrow's expected production, likely range and strongest hours. One useful email each day.
Method and data
Every city uses a 10 kWp system facing south at 35 degrees with 14% system losses. Tomorrow's figure combines hourly weather with GridPassport's PV production and uncertainty model. The monthly profile uses the European Commission JRC PVGIS multi-year climate series. Roof direction, shade, snow, dirt, inverter clipping and local weather can change real output.
CSV and JSON snapshots are published under CC BY 4.0 with source attribution.