Grandma's Surf Forecast

/ HAW – Maui (46 breaks) / Hawaii (267 breaks) /

USA (1297 breaks) / Lat Long: (20.79° N 156.56° W)

Surf Forecasts:

Grandma's surfForecast / HAW – Maui / USA

12 Day Weather and Surf, issued 7 am Tuesday 16 Sep 2025 HST

Forecast update in hr min s Forecast update imminent

Grandma's surf forecast is for near shore open water. Breaking waves will often be smaller at less exposed spots.

Today's Grandma's sea temperature is 27.1° C
(Which is normal for this time of year)

Best Forecast Surf Conditions for Grandma's this week:

The surf forecast for Grandma's over the next 12 days: The first swell (rated 1 star or higher) is forecast to arrive on Tuesday (Sep 16) at 2PM. The primary swell is predicted to be 0.4m and 13s period with a secondary swell of 0.2m and 5s. The wind is predicted to be cross-offshore as the swell arrives.

The most powerful waves expected at Grandma's in the next 12 days are 0.9m 15s and forecast to arrive on Saturday (Sep 20) at 11PM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.8m 6s period and expected on Wednesday (Sep 17) at 11PM.

Wave Type	Time (HST) & Date	Wave Height & Period
Next good surf (1 star+)	2PM (Tue 16th Sep)	1.5ft (0.4m) 13s
Best Surf	11PM (Fri 19th Sep)	2ft (0.6m) 17s
Most Powerful	11PM (Sat 20th Sep)	3ft (0.9m) 15s

Table - best surf conditions forecast for Grandma's over the next 12 days.

Updates in hr min s Forecast update imminent

12 Days Hourly

Print Table

	Short Range Forecast Mostly dry. Warm (max 28°C on Tue morning, min 24°C on Tue night). Wind will be generally light.									Days 3-6 Weather Summary Mostly dry. Warm (max 29°C on Sun afternoon, min 25°C on Fri night). Wind will be generally light.
	Tuesday 16			Wednesday 17			Thursday 18			Friday 19			Saturday 20			Sunday 21			Monday 22
	AM	PM	Night	AM	PM	Night	AM	PM	Night	AM	PM	Night	AM	PM	Night	AM	PM	Night	AM	PM	Night
Rating (10 max)	1	1	1	1	1	1	0	0	1	1	1	2	2	2	2	1	1	1	1	1	1
Swell Height Map See all maps
Wave Height (m) & direction (?)	SSW	SSW	SSW	SW	SW	SW	SW	SW	SSW	SSW	SSW	SSW	SSW	SSW	SSW	SSW	SSW	SSW	SSW	SSW	SSW
Period(s) (?)	12	13	16	16	15	15	14	14	13	19	18	16	16	15	15	14	13	13	13	12	12
Wave Graph (?)
kJ (?)	50	56	51	61	57	55	51	51	69	72	121	211	291	256	305	195	158	137	93	85	85
Wind (km/h)	NE	NNE	NNE	W	ENE	NNE	W	NNE	NNE	NNE	NE	NNE	NNE	NNE	N	NE	NE	NNE	NNW	NNE	NNE
Wind State (?) onshore cross-onshore cross-shore cross-offshore offshore glassy	off	off	cross- off	glass	off	cross- off	cross- on	cross- off	off	cross- off	off	off	glass	off	cross- off	glass	off	cross- off	cross- off	cross- off	off
High Tide / height (m)	12:30PM 0.78		12:57AM 0.35	1:19PM 0.78		1:45AM 0.41		2:02PM 0.76	2:27AM 0.46		2:40PM 0.73	3:06AM 0.52		3:14PM 0.68	3:43AM 0.56		3:46PM 0.63	4:19AM 0.60		4:16PM 0.57	4:55AM 0.63
Low Tide / height (m)		7:51PM 0.13		5:55AM 0.11		8:20PM 0.11	6:55AM 0.10		8:45PM 0.10	7:47AM 0.09		9:06PM 0.09	8:35AM 0.10		9:27PM 0.08	9:20AM 0.12		9:49PM 0.07	10:04AM 0.13		10:12PM 0.07

	Tuesday 16			Wednesday 17			Thursday 18			Friday 19			Saturday 20			Sunday 21			Monday 22
Sunrise	6:13	-	-	6:13	-	-	6:13	-	-	6:13	-	-	6:13	-	-	6:13	-	-	6:13	-	-
Sunset	-	6:28	-	-	6:27	-	-	6:25	-	-	6:24	-	-	6:23	-	-	6:22	-	-	6:22	-

Rain (mm)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Temp. °C	28	28	26	27	28	26	27	27	26	28	28	26	28	28	27	28	29	26	27	28	26
Feels °C (?)	28	29	27	29	31	28	29	30	27	29	29	27	32	30	30	31	30	28	29	31	27

Map Icons:
Break
Live Wave Height (m)
Live Wind Speed (km/h)
Surf Rating (10 Max)
Ocean Swells (m)
Wind Speed (km/h)

Recent Eyeball Surf Reports for HAW - Maui

Wind Update Offshore wind has become very light (calm at Kīhei wx 12 km from Grandma's). Surf should be turning clean at Grandma's. 0.4m 7s swell from the SE with a 0.2m 10s swell from the S and a 0.2m 12s groundswell from the SSE. 3 swells combining to make bigger set waves.
47 minutes ago Grandma's

Expand

View all

Actual: 47 min ago

5 km/h

NNE

Clean

Please reload the page to see if there are any updates.

FREE! Surf-Forecast.com widget for your website

The surf report / weather widget below is available to embed on third party websites free of charge and provides a summary of our Grandma's surf forecast. Simply grab the html code snippet that we provide and paste it into your own site. You can choose your preferred language and metric/imperial units for the surf forecast feed to suit users of your site. Click here to get the code.

Information about the Grandma's Surf forecast

The above surf forecast table for Grandma's provides essential information for determining whether the surfing conditions will be good over the next 12 days. A general guide to surfing at Grandma's can be found by selecting the local surf guide option on the grey menu. Our Grandma's surf forecast is unique since it includes wave energy (power) that defines the real feel of the surf rather than just the height or the period. If you surf the same spot (Grandma's) regularly then make a mental note of the wave energy from the surf forecast table each time you go. Very soon you may start to choose your surf days based on the wave energy alone combined with our forecast of favourable offshore wind conditions. Our star ratings will help here and of course you will also find the usual wave height and period predictions on our surf forecasts as well as a full break down of the swell components under our advanced users option (to reveal that, click the little Einstein character under the tide times).

Further information to help with frequently asked questions about our surf forecast for Grandma's may be found under the help tab on the top menu and also by moving your mouse over the question marks on the surf forecast table itself. Please always bear in mind that the forecast is for near-shore open water and local factors at each surf break influence the actual breaking wave height, such as the beach / reef profile, water depths offshore and shelter.

Are you planning a vacation in Maui? If you are looking for accommodation near Grandma's, camping, hotels and condos and appartments in Maui, consider staying in Kihei which is 10 km (6 miles) away. Other places in and around Maui where you can find information about places to rent, and car hire include Wailuku which is 12 km (7 miles) away, Kahului, Lanai - Lanai and Kaunakakai - Molokai.