Hiroshima vs Iwakuni: which is sunnier?
🇯🇵 Japan vs 🇯🇵 Japan · 70 km apart · long-term climate normals (NASA POWER, 2001–2020)
Hiroshima and Iwakuni are virtually tied for annual sunshine — about 1,773 vs 1,773 hours a year. Iwakuni has the higher Sunshine Score in 6 of 12 months; the other 6 are within 2 points.
Scores are the 0–100 Sunshine Score — sunshine, daytime warmth and dryness in one number, per month.
At a glance
| Hiroshima | Iwakuni | |
|---|---|---|
| Sunshine hours / year | 1,773 | 1,773 |
| Sunniest month | October (67/100) | October (67/100) |
| Nov–Feb average score | 11/100 | 27/100 |
| Jun–Aug average score | 63/100 | 62/100 |
| Rain / year | 1,527 mm | 1,621 mm |
| Warmest sea | 30°C / 86°F | 30°C / 86°F |
| Peak midday UV | 7 (high) | 7 (high) |
Hiroshima vs Iwakuni month by month
| Month | Sunshine Score | Day high °C | Rain mm | Sea °C | ||||
|---|---|---|---|---|---|---|---|---|
| Hiroshima | Iwakuni | Hiroshima | Iwakuni | Hiroshima | Iwakuni | Hiroshima | Iwakuni | |
| January | 0 | 7 | 6° | 9° | 60 | 56 | 14° | 14° |
| February | 0 | 19 | 8° | 11° | 73 | 76 | 12° | 12° |
| March | 17 | 34 | 11° | 14° | 104 | 109 | 12° | 12° |
| April | 50 | 55 | 17° | 18° | 118 | 128 | 16° | 16° |
| May | 63 | 61 | 22° | 22° | 142 | 153 | 18° | 18° |
| June | 61 | 61 | 25° | 25° | 208 | 242 | 22° | 22° |
| July | 61 | 61 | 28° | 28° | 240 | 268 | 26° | 26° |
| August | 66 | 64 | 29° | 30° | 127 | 138 | 30° | 30° |
| September | 61 | 61 | 26° | 27° | 179 | 181 | 29° | 28° |
| October | 67 | 67 | 20° | 23° | 121 | 119 | 25° | 24° |
| November | 44 | 56 | 15° | 17° | 76 | 77 | 21° | 21° |
| December | 0 | 25 | 8° | 12° | 79 | 74 | 16° | 16° |
The sunnier month by month: Jan Iwakuni · Feb Iwakuni · Mar Iwakuni · Apr Iwakuni · May even · Jun even · Jul even · Aug even · Sep even · Oct even · Nov Iwakuni · Dec Iwakuni.
When to pick which
- November–February: Iwakuni (average score 27/100 vs 11). Iwakuni is the warmer, around 12°C daytime highs vs 9°C. See the winter sun ranking.
- March–May: Iwakuni (average score 50/100 vs 43). Daytime highs are similar (17°C vs 18°C).
- June–August: too close to call — Hiroshima averages 63/100, Iwakuni 62/100. Daytime highs are similar (27°C vs 28°C).
- September–October: too close to call — Hiroshima averages 64/100, Iwakuni 64/100. Iwakuni is the warmer, around 25°C daytime highs vs 23°C.
Sea temperature
Both seas peak at 30°C / 86°F. Swimmable water (21°C+): Hiroshima about 6 months a year, Iwakuni about 6 months a year. Month-by-month sea temperatures are in the table above.
Full month-by-month guides: Hiroshima weather by month · Iwakuni weather by month · Best time to visit Japan.
More comparisons: Hiroshima vs Okayama · Hiroshima vs Matsuyama · Hiroshima vs Izumo · Iwakuni vs Matsuyama · Iwakuni vs Oita · all head-to-heads