Fire Island Water Temperature & Swim Forecast
Popular New York beach near Ocean Beach.
Mild water with a light chop and a light breeze — comfortable conditions for most swimmers.
Model estimate · modelled, not a buoy measurement. How accurate is this?
Location
Fire Island on the map, with nearby beaches and live sea temperatures.
7-day forecast
Water, air, waves, wind and UV outlook for the week ahead.
Shorty 2mm
At 19.4°C a 2mm shorty keeps surfers warm; lap swimmers can usually skip the neoprene.
Recommendation tuned for Fire Island's current water temperature. Individual tolerance, wind chill, and session length all matter — when in doubt, size up.
Fire Island swimming conditions summary
- Water temperature
- 19.4°C
- Water feels
- Refreshing
- Swimmable today
- Yes, but fresh — short swims or a wetsuit
- Swim conditions score
- 72/100 · Good
- Wetsuit needed
- Shorty 2mm
- Air temperature
- —
- Waves
- —
- Wind
- —
- UV index
- —
- Average sea temperature (September)
- 20.0 °C
- Warmest months to swim
- July, August, September
At 19.4°C a 2mm shorty keeps surfers warm; lap swimmers can usually skip the neoprene. 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 Fire Island right now?
The sea at Fire Island is currently 19.4°C — good 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 Fire Island next week?
Based on long-term September averages and the latest marine model, expect the sea around Fire Island to sit close to 17.1°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 Fire Island?
July – August – September are typically the warmest months to swim at Fire Island, with sea temperatures at their seasonal peak.
Do I need a wetsuit at Fire Island?
With water currently at 19.4°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 Fire Island today?
The sea is currently 19.4°C — good swimming conditions. Most swimmers will find it pleasant.
- • Located in New York, United States (Atlantic Ocean).
- • 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 Fire Island
The sea in Fire Island peaks in August, when the water averages around 23°C.
The main swimming season runs from July – September, when surface temperatures stay comfortable for extended sessions.
On average, 3 months a year sit above 20°C — the threshold most swimmers describe as pleasant without a wetsuit.
Shoulder months like June and October are noticeably cooler but often quieter, with fewer crowds and steadier weather.
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 3°C, when cold-water swimmers dominate the coast.
Fire Island sea temperature history
Long-term climatology for Fire Island shows an annual mean sea temperature of 12°C, ranging from 3°C in winter to 23°C at the summer peak.
The seasonal swing is roughly 20°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 Fire Island, 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.
Fire Island sea temperature: frequently asked questions
What is the warmest month to swim in Fire Island?
August is the warmest month in Fire Island, when the sea averages about 23°C. Late-season warmth often persists a few weeks after peak.
When is the sea coldest in Fire Island?
The coldest month in Fire Island is typically February, when the water averages around 3°C. Cold-water swimmers and surfers dominate this period.
When can you swim in Fire Island without a wetsuit?
The main swimming season in Fire Island runs from July – September — about 3 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 Fire Island?
Outside peak summer the water in Fire Island 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 Fire Island?
The long-term annual mean sea temperature in Fire Island is about 12°C, based on multi-decadal climatology of the surrounding waters.
How do I check the current sea temperature in Fire Island?
The live reading at the top of this page shows the current sea temperature in Fire Island, 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: Jul – Aug – Sep
| Month | Sea | Comfort |
|---|---|---|
| Jan | 4°C | Cold |
| Feb | 3°C | Cold |
| Mar | 4°C | Cold |
| Apr | 8°C | Cold |
| May | 13°C | Cold |
| Jun | 18°C | Pleasant |
| Jul | 22°C | Warm |
| Aug ⭐ | 23°C | Warm |
| Sep | 20°C | Pleasant |
| Oct | 16°C | Bracing |
| Nov | 11°C | Cold |
| Dec | 7°C | Cold |
Nearby beaches
The closest coastline, with live water temperatures.