Dublin vs Castletown: which is sunnier?
🇮🇪 Ireland vs 🇮🇲 Isle of Man · 130 km apart · long-term climate normals (NASA POWER, 2001–2020)
Dublin and Castletown are virtually tied for annual sunshine — about 1,488 vs 1,459 hours a year. Dublin has the higher Sunshine Score in 7 of 12 months, Castletown in 3 (2 within 2 points).
Scores are the 0–100 Sunshine Score — sunshine, daytime warmth and dryness in one number, per month.
At a glance
| Dublin | Castletown | |
|---|---|---|
| Sunshine hours / year | 1,488 | 1,459 |
| Sunniest month | July (60/100) | July (48/100) |
| Nov–Feb average score | 3/100 | 5/100 |
| Jun–Aug average score | 56/100 | 44/100 |
| Rain / year | 982 mm | 1,123 mm |
| Warmest sea | 17°C / 63°F | 16°C / 61°F |
| Peak midday UV | 5 (moderate) | 5 (moderate) |
Dublin vs Castletown month by month
| Month | Sunshine Score | Day high °C | Rain mm | Sea °C | ||||
|---|---|---|---|---|---|---|---|---|
| Dublin | Castletown | Dublin | Castletown | Dublin | Castletown | Dublin | Castletown | |
| January | 0 | 0 | 7° | 8° | 86 | 110 | 7° | 10° |
| February | 0 | 0 | 7° | 8° | 70 | 89 | 8° | 9° |
| March | 6 | 0 | 9° | 8° | 70 | 82 | 8° | 9° |
| April | 19 | 6 | 11° | 9° | 61 | 62 | 10° | 10° |
| May | 37 | 25 | 14° | 12° | 67 | 65 | 14° | 12° |
| June | 49 | 37 | 16° | 14° | 76 | 74 | 15° | 13° |
| July | 60 | 48 | 18° | 16° | 80 | 79 | 16° | 15° |
| August | 59 | 46 | 18° | 16° | 91 | 97 | 17° | 16° |
| September | 49 | 41 | 16° | 15° | 76 | 90 | 16° | 15° |
| October | 28 | 32 | 13° | 14° | 102 | 123 | 13° | 14° |
| November | 11 | 16 | 10° | 11° | 106 | 126 | 12° | 13° |
| December | 0 | 5 | 8° | 9° | 97 | 126 | 8° | 11° |
The sunnier month by month: Jan even · Feb even · Mar Dublin · Apr Dublin · May Dublin · Jun Dublin · Jul Dublin · Aug Dublin · Sep Dublin · Oct Castletown · Nov Castletown · Dec Castletown.
When to pick which
- November–February: too close to call — Dublin averages 3/100, Castletown 5/100. Daytime highs are similar (8°C vs 9°C). See the winter sun ranking.
- March–May: Dublin (average score 21/100 vs 10). Daytime highs are similar (11°C vs 10°C).
- June–August: Dublin (average score 56/100 vs 44). Dublin is the warmer, around 17°C daytime highs vs 15°C.
- September–October: too close to call — Dublin averages 39/100, Castletown 37/100. Daytime highs are similar (15°C vs 15°C).
Sea temperature
Dublin's sea gets warmer: 17°C / 63°F at its peak vs 16°C. Swimmable water (21°C+): Dublin never, Castletown never. Month-by-month sea temperatures are in the table above.
Full month-by-month guides: Dublin weather by month · Castletown weather by month · Best time to visit Ireland.
More comparisons: Dublin vs Belfast · Dublin vs Cork · Dublin vs Shannon · Castletown vs Liverpool · Castletown vs Belfast · all head-to-heads