Alnmouth Beach — Sea temperature now
Northumberland family beach.
Cool water with a light chop and a light breeze — fresh conditions — a wetsuit is recommended.
Location
Alnmouth Beach on the map, with nearby beaches and live sea temperatures.
7-day forecast
Water, air, waves, wind and UV outlook for the week ahead.
Monthly sea temperature averages
Typical year-round water temperature, based on regional climatology.
Best time to swim in Alnmouth Beach
The sea in Alnmouth Beach 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.
Alnmouth Beach sea temperature history
Long-term climatology for Alnmouth Beach 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 Alnmouth Beach, 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.
Alnmouth Beach sea temperature: frequently asked questions
What is the warmest month to swim in Alnmouth Beach?
August is the warmest month in Alnmouth Beach, when the sea averages about 17°C. Late-season warmth often persists a few weeks after peak.
When is the sea coldest in Alnmouth Beach?
The coldest month in Alnmouth Beach is typically February, when the water averages around 8°C. Cold-water swimmers and surfers dominate this period.
When can you swim in Alnmouth Beach without a wetsuit?
The sea in Alnmouth Beach 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 Alnmouth Beach?
Outside peak summer the water in Alnmouth Beach 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 Alnmouth Beach?
The long-term annual mean sea temperature in Alnmouth Beach is about 12°C, based on multi-decadal climatology of the surrounding waters.
How do I check the current sea temperature in Alnmouth Beach?
The live reading at the top of this page shows the current sea temperature in Alnmouth Beach, 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 |