Castlereagh Weather & Climate: Best Time to Visit
Average temperatures, rainfall, sunshine and the best time to visit Castlereagh.
Climate overview of Castlereagh
Castlereagh, Down County, United Kingdom, experiences moderate temperature changes through the seasons. July is the warmest month with daytime highs of 18°C (64°F), while January is the coolest at 9°C (48°F).
The city receives considerable rainfall, with around 1057 mm (42 in) annually. October is the wettest month. May is the sunniest month, averaging 6.1 hours of sunshine per day.
Castlereagh Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in Castlereagh - and find the best time to visit.
Monthly Temperature in Castlereagh
The weather in Castlereagh changes moderately throughout the year, offering enough variation to appreciate each season. Typically, average maximum daytime temperatures range from a pleasant 18°C (64°F) in July to a chilly 9°C (48°F) in the coolest month, January.
Nights vary from 13°C (55°F) in July to around 4°C (39°F) during the colder months.
Check out our detailed temperature page for more information.
Temperature ranges by month
Rainfall in Castlereagh
Castlereagh has a relatively rainy climate with high precipitation levels, averaging 1057 mm (42 in) of rainfall annually. Precipitation levels in Castlereagh remain relatively steady throughout the year. October has the most rain, with 103 mm (4.1 in) over 19 days. In the driest month March, this drops slightly to 74 mm (2.9 in), making the city's climate fairly predictable. For more details, please visit our Castlereagh Precipitation page.
The mean monthly precipitation over the year, including rain, hail, and snow
The average number of days each month with precipitation
Sunshine Hours in Castlereagh
For those who appreciate different seasons, Castlereagh serves as an ideal destination. Expect longer, more sun-filled days in May with an average of 6.1 hours of sunshine daily, and embrace the darker days in December, offering only 1.3 hours of daily sunlight.
Visit our detailed sunshine hours page for more information.
Monthly hours of sunshine
Daily hours of sunshine
Daily percentage of sunshine
Water Temperature in Castlereagh
The mean water temperature over the year ranges from 7°C (45°F) in February to 13°C (55°F) in August.
Water temperature over the year
Humidity in Castlereagh by Month
The city experiences its highest humidity in September, reaching 91%. In February, the humidity drops to its lowest level at 86%. What does this mean? Read our detailed page on humidity levels for further details.
Relative humidity over the year
Wind Speed in Castlereagh
The mean wind speed varies between 4 m/s (8 knots) and 5 m/s (10 knots) throughout the year. It is lowest in April, May, June, July, August and September and highest during January, February, March, October, November and December. What does this mean?
The mean monthly wind speed over the year (meters per second)
Best Time to Visit Castlereagh
Monthly ratings reflect general weather comfort, based on daytime temperature and rainfall. Swimming and winter conditions are highlighted separately where relevant.
- Best overall: July and August
- Warmest weather: July, August and September
- Most sunshine: May
Frequently asked questions about the climate in Castlereagh
What is the best time to visit Castlereagh?
July and August typically offer the most optimal weather in Castlereagh. In contrast, January, February, March, November and December tend to have less optimal conditions.
What temperatures can I expect in Castlereagh?
Daytime highs range from 9°C (48°F) in January to 18°C (64°F) in July. Nighttime lows range from 4°C (39°F) to 13°C (55°F).
How much rain does Castlereagh get?
Annual rainfall is around 1057 mm (42 in). October is the wettest month with 103 mm (4.1 in), while March is the driest with 74 mm (2.9 in).
How sunny is Castlereagh?
Castlereagh receives around 1,297 hours of sunshine per year. May is the sunniest month with 184 hours, while December is the cloudiest with just 39 hours.
Castlereagh 3-Day Forecast
Castlereagh on the map
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