Peak Sun Hours in Denver, Colorado, United States
- Solar zone
- Zone 3 (good)
- Best month
- June (7.2)
- Worst month
- December (2.3)
- Climate
- Continental · 9.0°C
Monthly solar breakdown
| Month | GHI | Clear-sky | DNI | DHI | Temp °C | Humid % |
|---|---|---|---|---|---|---|
| Jan | 2.59 | 3.29 | 4.51 | 1.02 | -1.7 | 55 |
| Feb | 3.54 | 4.53 | 5.02 | 1.37 | -1.4 | 56 |
| Mar | 4.73 | 6.08 | 5.69 | 1.73 | 3.2 | 52 |
| Apr | 5.77 | 7.58 | 6.05 | 2.06 | 7.2 | 50 |
| May | 6.47 | 8.51 | 6.26 | 2.28 | 12.5 | 49 |
| Jun | 7.22 | 8.81 | 7.39 | 2.12 | 19.4 | 41 |
| Jul | 7.00 | 8.41 | 7.16 | 2.04 | 22.3 | 45 |
| Aug | 6.31 | 7.51 | 6.77 | 1.87 | 20.7 | 46 |
| Sep | 5.37 | 6.29 | 6.92 | 1.42 | 16.4 | 44 |
| Oct | 3.98 | 4.84 | 6.07 | 1.15 | 8.7 | 48 |
| Nov | 2.87 | 3.53 | 5.10 | 0.97 | 2.8 | 51 |
| Dec | 2.29 | 2.92 | 4.34 | 0.88 | -2.1 | 56 |
GHI, Clear-sky, DNI, DHI in kWh/m²/day. Data: NASA POWER climatology (long-term monthly averages).
Off-grid calculator
Add appliances
- Add an appliance to size a system.
Sizing
- Daily load
- 0.00 kWh
- Panel wattage
- 0 W
- Panel count (400W modules)
- 0
- Battery bank
- 0.0 kWh
Sizing against worst-month PSH of 2.29 kWh/m²/day, 0.77 system efficiency.
About solar in Denver
Denver, United States has a continental climate with cold winters and warmer summers. Its annual peak sun hours average 4.84 kWh/m²/day, a good solar resource by global standards.
The strongest month in Denver is June (summer) at 7.22 kWh/m²/day, and the weakest is December (winter) at 2.29 kWh/m²/day. When sizing a year-round off-grid system, it's standard practice to design against the December value rather than the annual average — otherwise the battery bank runs low during the darkest weeks.
Denver's solar conditions are well within the range where off-grid PV is a straightforward engineering exercise with standard-sized arrays and lithium batteries.
FAQ
- What are the peak sun hours in Denver?
- Denver averages 4.84 peak sun hours per day annually, ranging from 2.29 in December to 7.22 in June.
- How many solar panels do I need in Denver?
- Panel count depends on your daily load. At Denver's annual average of 4.84 kWh/m²/day, a 5 kWh/day load needs roughly 4 × 400 W panels. Use the calculator above for your actual load.
- What size battery do I need in Denver?
- Sizing against Denver's worst month (December, 2.29 kWh/m²/day) with 2 days of autonomy at 80% depth of discharge, a 5 kWh/day load needs about a 12.5 kWh battery bank.
- How does Denver's solar resource compare globally?
- Denver sits in solar zone 3 out of 5 (where 5 is strongest) at 4.84 kWh/m²/day — good by global standards. For reference, top-tier desert sites average ~6.5 and high-latitude cities around 2.5 kWh/m²/day.
- Does snow block solar panels in Denver?
- Yes — snow cover can drop output to near zero. In Denver's winter months (around December), brush panels after significant snowfall or design with steep tilt (45°+) so snow slides off naturally.
- How much does winter hurt solar output in Denver?
- Denver's worst month is December at 2.29 kWh/m²/day versus 7.22 in June — a 102% seasonal swing. Off-grid continental systems usually combine oversized arrays with wood-stove or generator backup.
- Is solar worth it in a continental climate like Denver's?
- Yes, but the seasonal ratio matters. Denver's annual 4.84 kWh/m²/day is solid; grid-tied net metering works well (summer credits offset winter draw). Full off-grid needs generator or hydro backup.