Manly Beach by Maksym Kozlenko, CC BY-SA 3.0
Manly Beach water temperature
The sea at Manly Beach averages 23°C (74°F) in February and 18°C (65°F) in August (NOAA OISST, 1991-2020).
Updated Tue Nov 3, 2026. These are long-term averages, not a forecast.
When is the water warmest at Manly Beach?
The water at Manly Beach is warmest from December to May, the months when the monthly average, in whole degrees, is within 2°C (3.6°F) of the yearly peak of 23°C (74°F) in February.
Dark bars are the warmest-water months. Bars show whole °C, which is what the warm-water rule uses; the table below has °C and °F.
How warm is the water at Manly Beach each month?
Sea temperature: NOAA OISST, 1991-2020.
| Month | Sea temperature |
|---|---|
| January | 23°C (73°F) |
| February | 23°C (74°F) |
| March | 23°C (74°F) |
| April | 22°C (72°F) |
| May | 21°C (70°F) |
| June | 20°C (67°F) |
| July | 19°C (65°F) |
| August | 18°C (65°F) |
| September | 18°C (65°F) |
| October | 19°C (67°F) |
| November | 20°C (68°F) |
| December | 21°C (71°F) |
Shaded rows: the warmest-water months.
Best time to visit Manly Beach
Going by sea temperature alone, the best time to visit Manly Beach for warm water is December to May. The sea is coolest in August, at 18°C (65°F). This does not consider air temperature, rain or crowds.
This is based on sea temperature averages only. It is not the Beach Score, which rates one hour from the forecast for wind, waves, weather and temperature: how the Beach Score works, or see today's score at Manly Beach.
These beaches share this forecast area and its averages: Freshwater Beach.
Sources and method
Sea temperature: NOAA OISST v2 high resolution long-term mean (sst.mon.ltm.1991-2020.nc, NOAA PSL, public domain), grid cell centered 33.875S 151.375E, 12 km from the forecast cell center. Period 1991-2020.
We do not show rain or air temperature: the global datasets we can use are too coarse to be right at a single stretch of coast.
Warmest-water months are the months whose average sea temperature, in whole degrees as shown, is within 2°C (3.6°F) of the warmest month's. Today's reading is the model forecast for the sea surface and can differ from a thermometer in the water.
Rip current and water quality data are not available for Manly Beach. Check local flags and lifeguards.