Castletown weather by month & the best time to visit
🇮🇲 Isle of Man · seaside town · oceanic / maritime climate
The best time to visit Castletown is July — its sunniest month (Sunshine Score 48/100), with August and September close behind. Castletown averages about 1,459 hours of sunshine a year. Daytime highs around 16°C / 61°F and roughly 79 mm of rain in July.
Jump to: month-by-month table · sea temperature · nearby alternatives · embed this data
- Sun hours / year
- 1,459
- Sunniest month
- July
- Peak score
- 48/100
- Rain / year
- 1,123 mm
- Midday UV at peak
- 5 (moderate)
- Sea at warmest
- 16°C / 61°F
- Population
- 3k
- Elevation
- 9 m
When is the best time to visit Castletown?
For sunshine, the best time to visit Castletown is July, then August and September. The dullest month is January (0/100, 110 mm of rain). The full month-by-month picture is in the table below.
How sunny is Castletown?
Castletown isn't a sunny place by world standards: about 1,459 hours of sunshine a year. 48 Sunshine Score points separate July (48) from January (0), so the month you pick matters. It is the only destination Sunshine Map tracks in Isle of Man. The year's 1,123 mm of rain spreads fairly evenly across the months, with no pronounced dry season.
Sunshine Score by month
| Month | Score | Day high | Night low | Rain | UV | Sea |
|---|---|---|---|---|---|---|
| January | 0 | 8° / 46°F | 6° / 43°F | 110 mm | 0 | 10° / 50°F |
| February | 0 | 8° / 46°F | 6° / 43°F | 89 mm | 1 | 9° / 48°F |
| March | 0 | 8° / 46°F | 6° / 43°F | 82 mm | 2 | 9° / 48°F |
| April | 6 | 9° / 48°F | 7° / 45°F | 62 mm | 3 | 10° / 50°F |
| May | 25 | 12° / 54°F | 10° / 50°F | 65 mm | 4 | 12° / 54°F |
| June | 37 | 14° / 57°F | 12° / 54°F | 74 mm | 5 | 13° / 55°F |
| July | 48 | 16° / 61°F | 14° / 57°F | 79 mm | 4 | 15° / 59°F |
| August | 46 | 16° / 61°F | 15° / 59°F | 97 mm | 4 | 16° / 61°F |
| September | 41 | 15° / 59°F | 14° / 57°F | 90 mm | 3 | 15° / 59°F |
| October | 32 | 14° / 57°F | 12° / 54°F | 123 mm | 1 | 14° / 57°F |
| November | 16 | 11° / 52°F | 9° / 48°F | 126 mm | 0 | 13° / 55°F |
| December | 5 | 9° / 48°F | 8° / 46°F | 126 mm | 0 | 11° / 52°F |
Sea temperature in Castletown by month
The sea off Castletown is warmest in August at around 16°C / 61°F, and coolest in February at 9°C / 48°F. It never reaches comfortable swimming temperatures (21°C+). Month-by-month sea-surface temperatures are in the Sea column of the table above.
See Castletown on the interactive sunshine globe →
Nearby places for sunshine
- Belfast United Kingdom · 121 km · best in Jul · 1,263 h sun/yr
- Dublin Ireland · 130 km · best in Jul · 1,488 h sun/yr
- Liverpool United Kingdom · 143 km · best in Jul · 1,453 h sun/yr
- Glasgow United Kingdom · 158 km · best in Jul · 1,304 h sun/yr
- Manchester United Kingdom · 175 km · best in Jul · 1,454 h sun/yr
- Leeds United Kingdom · 195 km · best in Jul · 1,444 h sun/yr
Nearest destinations
- Campbeltown United Kingdom · 165 km · 1,303 h sun/yr · best in Jul
Head-to-head
How Castletown compares month by month: Castletown vs Dublin · Castletown vs Liverpool · Castletown vs Belfast · all comparisons
Put the Castletown sunshine badge on your site
A compact badge showing Castletown's sunshine at a glance — free to embed under CC BY 4.0. Paste this wherever you'd like it to appear:
Live preview — this is exactly what your readers see: