Diving and snorkeling in Niu
Today, Wednesday, October 28, 2026 · local time (HST) · Hawaii, United States Today, Wed, Oct 28 · HST- Slack water
- 4:29–5:00 am, 11:40 am–1:00 pm, 3:20–5:00 pm and 9:20–10:20 pm
- Swell
- 3.6 ft, 11 s
- Water and suit
- 79.2 °F · Shorty or a rash guard
- Likely visibility
- Poor
- Water (satellite)
- Very clear
Today, Wednesday, October 28, the best time to dive in Niu is 10:50 am to 11:30 am, with light wind and the sun high, though with some swell and current. It's a fair day (3/10). Visibility is likely poor. Water at 79.2 °F: a shorty or a rash guard. The best day this week is Tuesday, November 3, at 5/10.
Your diving day in Niu at a glance
The strip runs from midnight to midnight, local time. Daylight on top; then the tide with its slack water (purple bands), the conditions hour by hour and the best times.
Today in detail
Likely visibility: poor- Slack water today: high tide 4:44 am (4:29–5:00 am), low tide 12:19 pm (11:40 am–1:00 pm), high tide 4:10 pm (3:20–5:00 pm) and low tide 9:56 pm (9:20–10:20 pm)
- Likely visibility: poor. Swell (up to 3.9 ft at 11 s) and rain (3.25 in) over the last few days have stirred up the water. Based on the last 24 hours of data.
- Water at 79.2 °F: a shorty or a rash guard.
- Snorkeling: better not, with these waves, wind or current.
- Night dive: dark from 6:20 pm. Waning gibbous (90%), rising at 8:20 pm: a bright night.
How deep it gets off the shore
33 ft deep 0.55 mi from shore; 66 ft is far out (1.6 mi): for deeper dives, go by boat.
Source: NOAA U.S. Coastal Relief Model (public domain), cells of about 300 ft. For reference only: not for navigation or anchoring.
Slack water comes from the tide: in inlets, channels and between islands the water can keep running for an hour or two after. Ask the local dive shop.
Never dive alone and check with the local dive shop: this rating is a guide, not a substitute for a professional.
The water, as seen by satellite
The satellite saw very clear water in the sea off Niu, within 3.1 mi (one pixel of 2.5 mi; Kd490 = 0.036 m⁻¹). Kd490 measures how fast blue light fades with depth: the higher it is, the murkier the water, from plankton, suspended sand or rivers.
Very clear: under 0.06 m⁻¹ (open tropical sea: Red Sea, Caribbean). Clear: up to 0.12. Slightly murky: up to 0.25. Murky: above that (coasts with rivers, estuaries).
It's what the satellite saw that day, the last one without clouds: since then, swell, wind or rain may have changed it. The likely visibility above is today's.
Satellite: NOAA CoastWatch, Kd490 from the S-NPP VIIRS (experimental product), 2.5 mi pixels. It only shows where the seabed drops below 20 m close to shore: in shallower water the satellite sees the bottom and makes the water look murkier than it is. Sources and licenses
Diving forecast for the next 7 days
| Day | Rating | Best times | Swell | Visibility | Water |
|---|---|---|---|---|---|
| Today | 3 fair day | 10:50–11:30 am9:10–9:50 am | 3.6 ft · 11 s | Poor | 79.2 °F · Shorty or a rash guard |
| Thu 29 | 3 fair day | 6:30–7:10 am12:30–1:30 pm | 2.8 ft · 9 s | Poor | 79.3 °F · Shorty or a rash guard |
| Fri 30 | 2 poor day | 1:10–2:30 pm6:30–7:10 am | 3.8 ft · 11 s | Poor | 79.3 °F · Shorty or a rash guard |
| Sat 31 | 4 fair day | 7:20–9:00 am2:50–5:20 pm | 3.0 ft · 11 s | Poor | 79.5 °F · Shorty or a rash guard |
| Sun 1 | 4 fair day | 8:10–10:00 am6:30–7:10 am | 2.9 ft · 10 s | Poor | 79.5 °F · Shorty or a rash guard |
| Mon 2 | 4 fair day | 4:10–5:50 pm9:10–10:50 am | 1.9 ft · 10 s | Fair | 79.5 °F · Shorty or a rash guard |
| Tue 3 | 5 average day | 4:50–5:50 pm10:10–11:40 am | 1.5 ft · 8 s | Fair | 79.3 °F · Shorty or a rash guard |
Each day's rating comes from the swell, waves, wind, current, slack water, daylight and likely visibility. The forecast reaches about 7 days.
Dive sites, wrecks and dive shops nearby
Map: OpenFreeMap · © OpenMapTiles · © OpenStreetMap contributors
- Hanauma Bay central Fish seen: Lavender Tang, Saddle-back wrasse, Short-tail bristle-tooth, Convict Tang 2.6 mi
- Natatorium Fish seen: Rhinecanthus rectangulus, Saddle-back wrasse, White-spotted Puffer, Plectroglyphidodon imparipennis 6.2 mi
- Fort Derussy Fish seen: Pycnochromis vanderbilti, Saddle-back wrasse, Belted Wrasse, Banded Goatfish 6.7 mi
- Ala Moana Fish seen: Lavender Tang, Saddle-back wrasse, Banded Goatfish, White-spotted Puffer 7.9 mi
- Kewalo Pipe Fish seen: Saddle-back wrasse, Lavender Tang, White-spotted Puffer, Sufflamen bursa 7.9 mi
- Wreck 0.9 mi
- Wreck 7.9 mi
- Maunalua Bay Artificial Reef - Tires 2.8 mi
- Maunalua Bay Artificial Reef - Navy LCU 2.9 mi
- Island Divers Hawaii 1.9 mi
- Scuba Diving 2.0 mi
- Bob's Hawaii Adventure 2.1 mi
Within 12 mi. Some may be missing or closed; marine reserves usually need a permit. Open the map on OpenStreetMap · Missing one? Add it to OpenStreetMap
Wreck and reef positions are approximate and not for navigation; a wreck’s depth runs from the top of the hull to the seabed.
Sites: © OpenStreetMap contributors (ODbL). US wrecks: NOAA electronic navigational charts (ENC), a U.S. Government work; not for navigation. Sites and fish: Reef Life Survey / IMOS NRMN, CC BY 4.0; fish names, Wikidata. Artificial reefs: NOAA and BOEM (MarineCadastre.gov), a U.S. Government work.
Coral in the area
NOAA's Coral Reef Watch satellites track water heat on coral reefs every day. In the “Main Hawaiian Islands” area, which this place is in, on October 27: Bleaching watch: the water is already a little above normal for the warmest month; there's no worrying build-up of heat yet.
- Alert level
- Bleaching watch
- Heat build-up (12 weeks)
- 0.1 °C-weeks · steady
- Water vs. normal
- 1.4 °F warmer than normal
Heat build-up adds up, week by week over the last three months, how far the water goes above its normal summer maximum. According to Coral Reef Watch, significant bleaching is likely from 4 °C-weeks and severe bleaching with mortality from 8.
Satellite: NOAA Coral Reef Watch (reef areas, 3.1 mi pixels). It covers the whole area, not this exact spot. Sources and licenses
How we work out the diving rating
We score every moment of the day, every 10 minutes, from 0 to 10, with simple fixed rules:
- Swell: takes points away based on its height and period (a 10 s swell weighs 50% more than a 6 s one, because it reaches deeper and moves the bottom): nothing under 1.6 ft, up to 6.5 points from 9.8 ft. Surface waves count for getting in and out; we take the worse of the two.
- Wind: takes points away from force 4, about 12 mph (1 point), up to 6 points in a gale; half a point more when it blows offshore, because it pushes surface swimmers away from shore.
- Current: Météo-France's model current takes points away from half a knot (1 point) up to 6 points from 2 knots.
- Slack water: where we show the tide, up to 3 points come off when the water rises or falls fast (mid-tide, especially on spring tides) and none at slack, around each high and low tide.
- Light: half a point more with the sun high (3 hours either side of solar noon), 1.5 less at twilight and 3 less at night. Thunderstorms take away 5 and heavy rain 1.
- Likely visibility: good, fair or poor from the swell of the previous 48 hours, the rain of the previous 72 and the wind of the previous 24. Fair takes 1 point off the day's rating and poor, 2.
- Day's rating: the average of the best window (the stretch of 40 minutes to 3 hours with the best conditions), adjusted for likely visibility.
- Wetsuit, by water temperature: below 50 °F, drysuit; from 50 °F, 7 mm semi-dry; from 57 °F, 7 mm wetsuit; from 64 °F, 5 mm; from 72 °F, 3 mm; from 79 °F, shorty or rash guard.
Today: the best window scores 5.2 out of 10 and visibility is likely poor, so it takes 2 off.
It's an estimate from the swell, rain and wind of the previous days, not a measurement: real visibility also depends on the bottom, plankton and nearby rivers.
Separately, when there is data, the water clarity the satellite saw in the last few days (NOAA CoastWatch Kd490, 4 km pixels): it does not change the rating.
Slack water comes from the tide: in inlets, channels and between islands the water can keep running for an hour or two after. Ask the local dive shop.
It is a guide built from models, not a guarantee: every site has its own currents and bottom. Look at the water when you get there and ask the dive shop.
Before you get in the water
- Never dive alone: always with a buddy and, if you don't know the site, with a dive shop.
- Check with the local dive shop or club: they know the currents, the no-dive zones and how the water is today.
- Dive within your certification and experience, and stay within depth and no-decompression limits.
- Fly a dive flag (diver-down or alpha flag) on a float and watch for boat traffic.
- Marine reserves need a permit and often have quotas: ask before you go.
- This rating doesn't replace a professional's judgment or what you see when you arrive: if the sea doesn't look right, don't go in.
Questions about diving in Niu
Can you dive in Niu today?
Today is a fair day (3/10). The best time is 10:50 am to 11:30 am, with light wind and the sun high, though with some swell and current.
What about tomorrow? When's the best time to dive in Niu?
Tomorrow, Thursday, October 29: 6:30 am to 7:10 am, with a rating of 3/10.
Which day this week is best for diving in Niu?
Tuesday, November 3, at 5/10. Its best time is 4:50 pm to 5:50 pm.
When is slack water in Niu today?
Today the water barely runs at these times: high tide 4:44 am (4:29–5:00 am), low tide 12:19 pm (11:40 am–1:00 pm), high tide 4:10 pm (3:20–5:00 pm) and low tide 9:56 pm (9:20–10:20 pm). It's an estimate from the tide: in inlets and channels slack water can come later. Ask the local dive shop.
What will the visibility be like in Niu?
Likely poor. Swell (up to 3.9 ft at 11 s) and rain (3.25 in) over the last few days have stirred up the water. Based on the last 24 hours of data. It's an estimate, not a measurement.
What wetsuit do I need to dive in Niu?
Water at 79.2 °F: a shorty or a rash guard. If you get cold easily or plan several dives, go thicker.
Can you dive at night?
Yes, with experience, a primary and a backup light, and ideally with a dive shop. Night dive: dark from 6:20 pm. Waning gibbous (90%), rising at 8:20 pm: a bright night.
How is the rating worked out?
From the swell and its period, the waves, the wind, the current, slack water, daylight and likely visibility. Each factor adds or takes away a fixed number of points and the rating sums up the best window of the day out of 10.
More about Niu today
Learn more
Our own calculation: tide from Hanauma Bay (NOAA), sun and moon with astronomy-engine, and sea and weather from Open-Meteo (Météo-France, ECMWF, NOAA GFS and Copernicus Marine, CC BY 4.0). Dive sites: © OpenStreetMap contributors (ODbL). Slackwater database (https://github.com/openwatersio/slackwater-database)