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Solar and backup power in St. John's
St. John's, Newfoundland and Labrador, gets 3.02 peak sun hours a day on average. The dullest month is December at 0.82 hours, 84% less than June, the sunniest at 4.99. That makes it sunnier than 10% of the 21 cities we cover in Canada.
Sunshine in St. John's is clearly below its yearly average for 5 months, from October to February. That stretch decides how many panels you need if solar has to keep up all year. Across the year, St. John's gets 13% less sunshine than the average of the cities we cover in Canada.
What a home in St. John's needs
Three example homes, each covering a 12-hour daily outage with a lithium battery and solar panels to recharge it. Panels are 450 W. The month-with-least-sun figure is what keeps you covered all year.
| Home | Inverter | Battery | Panels, December | Panels, yearly average |
|---|---|---|---|---|
| Essentials 6 lights, 2 fans, a fridge, TV, Wi-Fi and phone charging | 1 kW | 2.6 kWh | 8 | 3 |
| Family home Essentials plus a freezer, more lights, a laptop, a desktop and a water pump | 3 kW | 7.4 kWh | 22 | 6 |
| With air conditioning The family home plus two small air conditioners for 6 hours a day | 5 kW | 14.9 kWh | 44 | 12 |
December sunshine in St. John's is weak, at 0.82 peak sun hours a day, so covering outages with solar alone that month needs a very large array. Most homes here size panels for spring to autumn and recharge batteries from the grid or a generator in the darkest weeks. Switch the calculator to "Yearly average" to see that size.
Your own appliances will differ. Put them into the calculator below, which already has St. John's's sunshine.
Size your own system in St. John's
Planning tips for St. John's
- Size panels for December, not for the yearly average. A system sized on the average falls short in the dullest weeks, which is when you most need it.
- Dust, heat and shade cut output. Keep panels clean, leave air space under them, and avoid anything that shades them between mid-morning and mid-afternoon.
- Ask installers for the inverter's continuous and surge ratings, the battery's usable capacity and chemistry, and the panels' total watts. Compare those numbers with your plan rather than the package name.
Guides for planning in St. John's
- Peak sun hours and your dullest month
- How many solar panels you need
- Lithium vs lead-acid batteries
- Questions to ask an installer
Nearby cities
- Charlottetown 804 km · 3.31 h
- Halifax 898 km · 3.54 h
- Fredericton 1077 km · 3.52 h
- Québec 1398 km · 3.44 h
- Montréal 1608 km · 3.54 h
- Ottawa 1770 km · 3.6 h
Sunshine: NASA POWER climatology, ALLSKY_SFC_SW_DWN, monthly averages for 25-year Meteorological and Solar Monthly & Annual Climatologies (January 2001 - December 2025), at 47.5649, -52.7093; retrieved 2026-11-09. Peak sun hours equal kWh of sunlight per square metre per day on flat ground; tilted panels usually collect a little more.