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Peak Sun Hours in Daejeon, Daejeon, South Korea

3.9
kWh/m²/day (annual avg)
Solar zone
Zone 2 (moderate)
Best month
May (5.6)
Worst month
December (2.2)
Climate
Temperate · 11.1°C

Monthly solar breakdown

J: 2.46 kWh/m²/day F: 3.22 kWh/m²/day M: 4.24 kWh/m²/day A: 4.96 kWh/m²/day M: 5.57 kWh/m²/day J: 5.11 kWh/m²/day J: 4.18 kWh/m²/day A: 4.36 kWh/m²/day S: 4.01 kWh/m²/day O: 3.56 kWh/m²/day N: 2.54 kWh/m²/day D: 2.21 kWh/m²/day J F M A M J J A S O N D 7 0
Month GHI Clear-sky DNI DHI Temp °C Humid %
Jan 2.46 3.15 3.37 1.12 -3.7 81
Feb 3.22 4.08 3.56 1.47 -1.1 76
Mar 4.24 5.31 3.80 1.89 3.8 74
Apr 4.96 6.47 3.89 2.20 10.3 72
May 5.57 7.19 3.87 2.58 16.7 71
Jun 5.11 7.11 2.61 2.85 21.8 71
Jul 4.18 6.86 1.80 2.55 24.3 84
Aug 4.36 6.42 2.50 2.38 24.6 84
Sep 4.01 5.59 2.93 2.05 19.5 82
Oct 3.56 4.44 3.78 1.52 12.9 79
Nov 2.54 3.31 3.37 1.09 5.6 79
Dec 2.21 2.86 3.40 0.95 -1.6 80

GHI, Clear-sky, DNI, DHI in kWh/m²/day. Data: NASA POWER climatology (long-term monthly averages).

Off-grid calculator

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Sizing

Daily load
0.00 kWh
Panel wattage
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Panel count (400W modules)
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Battery bank
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Sizing against worst-month PSH of 2.21 kWh/m²/day, 0.77 system efficiency.

About solar in Daejeon

Daejeon, South Korea has a temperate climate with meaningful seasonal variation in solar resource. Its annual peak sun hours average 3.87 kWh/m²/day, a moderate solar resource by global standards.

The strongest month in Daejeon is May (spring) at 5.57 kWh/m²/day, and the weakest is December (winter) at 2.21 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.

Given the moderate resource, Daejeon installations typically oversize panels or combine solar with another source (grid, generator, hydro) for reliability.

FAQ

What are the peak sun hours in Daejeon?
Daejeon averages 3.87 peak sun hours per day annually, ranging from 2.21 in December to 5.57 in May.
How many solar panels do I need in Daejeon?
Panel count depends on your daily load. At Daejeon's annual average of 3.87 kWh/m²/day, a 5 kWh/day load needs roughly 5 × 400 W panels. Use the calculator above for your actual load.
What size battery do I need in Daejeon?
Sizing against Daejeon's worst month (December, 2.21 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 Daejeon's solar resource compare globally?
Daejeon sits in solar zone 2 out of 5 (where 5 is strongest) at 3.87 kWh/m²/day — moderate by global standards. For reference, top-tier desert sites average ~6.5 and high-latitude cities around 2.5 kWh/m²/day.
How much does winter reduce solar output in Daejeon?
Daejeon's worst month (December) delivers 2.21 kWh/m²/day — about 40% of the summer peak of 5.57. Off-grid systems here typically oversize 1.5–2× or pair with a backup source.
Do cloudy days significantly affect Daejeon's solar?
Partly. Diffuse light still produces 10–25% of clear-sky output. Daejeon's 3.87 kWh/m²/day already reflects average cloudiness, so no further derating is needed for sizing.
What panel tilt works best in Daejeon?
At Daejeon's latitude (36°), a fixed tilt near 36° balances year-round yield. Winter-heavy loads favor latitude + 15°; summer-heavy, latitude − 15°.