Portstewart Strand Water Temperature & Swim Forecast
Northern Ireland family beach.
Fresh water with a light chop and a light breeze — fresh conditions — a wetsuit is recommended.
Model estimate · modelled, not a buoy measurement. How accurate is this?
Location
Portstewart Strand on the map, with nearby beaches and live sea temperatures.
7-day forecast
Water, air, waves, wind and UV outlook for the week ahead.
3/2mm fullsuit
At 16.3°C a 3/2mm fullsuit is the standard wetsuit for surfing and watersports.
Recommendation tuned for Portstewart Strand's current water temperature. Individual tolerance, wind chill, and session length all matter — when in doubt, size up.
Portstewart Strand swimming conditions summary
- Water temperature
- 16.3°C
- Water feels
- Refreshing
- Swimmable today
- Yes, but fresh — short swims or a wetsuit
- Swim conditions score
- 59/100 · Fair
- Wetsuit needed
- 3/2mm fullsuit
- Air temperature
- —
- Waves
- —
- Wind
- —
- UV index
- —
- Average sea temperature (September)
- 16.0 °C
- Warmest months to swim
- July, August, September
At 16.3°C a 3/2mm fullsuit is the standard wetsuit for surfing and watersports. Model estimate. Water, wave, wind and UV values are Open-Meteo marine/weather model estimates, refreshed hourly — not buoy measurements.
Frequently asked questions
Can I swim at Portstewart Strand right now?
The sea at Portstewart Strand is currently 16.3°C — fresh swimming conditions. Most swimmers will find the water comfortable when it's above 22°C; below 18°C feels fresh and a wetsuit is recommended.
What will the sea temperature be at Portstewart Strand next week?
Based on long-term September averages and the latest marine model, expect the sea around Portstewart Strand to sit close to 14.6°C over the next 7 days. Check the live 7-day chart above for the exact daily outlook.
When is the best month to swim at Portstewart Strand?
July – August – September are typically the warmest months to swim at Portstewart Strand, with sea temperatures at their seasonal peak.
Do I need a wetsuit at Portstewart Strand?
With water currently at 16.3°C: above 22°C no wetsuit needed; 18–22°C a shorty is comfortable for long swims; 14–18°C a 3/2mm full suit; below 14°C a 4/3mm or thicker.
Can I swim at Portstewart Strand today?
The sea is currently 16.3°C — fair swimming conditions. Acclimatised swimmers will be most comfortable.
- • Located in Northern Ireland, United Kingdom (North Channel).
- • Family friendly with calm, accessible water.
- • Live data refreshed hourly from Open-Meteo Marine.
Monthly sea temperature averages
Tap any month to see what to expect — based on regional climatology.
Best time to swim in Portstewart Strand
The sea in Portstewart Strand peaks in August, when the water averages around 17°C.
On average, 0 months a year sit above 20°C — the threshold most swimmers describe as pleasant without a wetsuit.
Outside peak season the water drops toward 9°C, so a 3/2mm shorty or full wetsuit makes long swims much more comfortable.
The coldest month is typically February at around 8°C, when cold-water swimmers dominate the coast.
Portstewart Strand sea temperature history
Long-term climatology for Portstewart Strand shows an annual mean sea temperature of 12°C, ranging from 8°C in winter to 17°C at the summer peak.
The seasonal swing is roughly 9°C between the coldest and warmest month — a useful yardstick when comparing years or checking whether the current sea is running above or below average.
Recent decades have trended slightly warmer at Portstewart Strand, in line with regional sea-surface temperature records for the wider basin.
Monthly averages below are drawn from multi-decadal climatology and are updated as new observations arrive.
Portstewart Strand sea temperature: frequently asked questions
What is the warmest month to swim in Portstewart Strand?
August is the warmest month in Portstewart Strand, when the sea averages about 17°C. Late-season warmth often persists a few weeks after peak.
When is the sea coldest in Portstewart Strand?
The coldest month in Portstewart Strand is typically February, when the water averages around 8°C. Cold-water swimmers and surfers dominate this period.
When can you swim in Portstewart Strand without a wetsuit?
The sea in Portstewart Strand rarely climbs above 20°C, so a wetsuit is recommended year-round for anything longer than a quick dip.
Do I need a wetsuit in Portstewart Strand?
Outside peak summer the water in Portstewart Strand drops toward 9°C, so a 3/2mm shorty or full wetsuit makes long swims much more comfortable. In peak months most swimmers go without.
What is the average sea temperature in Portstewart Strand?
The long-term annual mean sea temperature in Portstewart Strand is about 12°C, based on multi-decadal climatology of the surrounding waters.
How do I check the current sea temperature in Portstewart Strand?
The live reading at the top of this page shows the current sea temperature in Portstewart Strand, updated hourly from marine buoy and satellite data. The 7-day forecast covers water, air, waves, wind and UV for the week ahead.
Year-round sea temperature
| Month | Sea | Comfort |
|---|---|---|
| Jan | 9°C | Cold |
| Feb | 8°C | Cold |
| Mar | 8°C | Cold |
| Apr | 9°C | Cold |
| May | 11°C | Cold |
| Jun | 14°C | Bracing |
| Jul | 16°C | Bracing |
| Aug ⭐ | 17°C | Bracing |
| Sep | 16°C | Bracing |
| Oct | 14°C | Bracing |
| Nov | 12°C | Cold |
| Dec | 10°C | Cold |
Nearby beaches
The closest coastline, with live water temperatures.