La Union San Juan — Sea temperature now
Coastal beach near San Juan.
Very warm water with a light chop and a light breeze — great swimming conditions.
Location
La Union San Juan 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 La Union San Juan
The sea in La Union San Juan peaks in May, when the water averages around 29°C.
The main swimming season runs from January – December, when surface temperatures stay comfortable for extended sessions.
On average, 12 months a year sit above 20°C — the threshold most swimmers describe as pleasant without a wetsuit.
The coldest month is typically January at around 26°C, when cold-water swimmers dominate the coast.
La Union San Juan sea temperature history
Long-term climatology for La Union San Juan shows an annual mean sea temperature of 28°C, ranging from 26°C in winter to 29°C at the summer peak.
The seasonal swing is roughly 3°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 La Union San Juan, 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.
La Union San Juan sea temperature: frequently asked questions
What is the warmest month to swim in La Union San Juan?
May is the warmest month in La Union San Juan, when the sea averages about 29°C. Late-season warmth often persists a few weeks after peak.
When is the sea coldest in La Union San Juan?
The coldest month in La Union San Juan is typically January, when the water averages around 26°C. Cold-water swimmers and surfers dominate this period.
When can you swim in La Union San Juan without a wetsuit?
The main swimming season in La Union San Juan runs from January – December — about 12 months a year when the sea sits above 20°C, the level most swimmers describe as pleasant without a wetsuit.
Do I need a wetsuit in La Union San Juan?
La Union San Juan stays warm year-round, so most swimmers never need a wetsuit — a rash guard is usually enough for sun and wildlife protection.
What is the average sea temperature in La Union San Juan?
The long-term annual mean sea temperature in La Union San Juan is about 28°C, based on multi-decadal climatology of the surrounding waters.
How do I check the current sea temperature in La Union San Juan?
The live reading at the top of this page shows the current sea temperature in La Union San Juan, 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
Best swim months: Jan – Feb – Mar – Apr – May – Jun – Jul – Aug – Sep – Oct – Nov – Dec
| Month | Sea | Comfort |
|---|---|---|
| Jan | 26°C | Hot |
| Feb | 26°C | Hot |
| Mar | 27°C | Hot |
| Apr | 28°C | Hot |
| May ⭐ | 29°C | Hot |
| Jun | 29°C | Hot |
| Jul | 28°C | Hot |
| Aug | 28°C | Hot |
| Sep | 28°C | Hot |
| Oct | 28°C | Hot |
| Nov | 27°C | Hot |
| Dec | 27°C | Hot |