Dee Why Sea Temperature

Looking to find out what the sea water temperature in Dee Why is for today and the next few days? Below are data and charts that will give you information about sea temperatures in Dee Why and nearby locations.

Water temperature in Dee Why right now

Below is the current sea temperature for Dee Why, Australia on 17th July 2025.

17.53° C

(63.56° F)

yesterday: 18.18° C (64.72° F)
a week ago: 18.42° C (65.16° F)

At this temperature, water will feel cold compared to a swimming pool, but with a bit of experience and practice most people will find the water relatively comfortable to swim in.

The average sea temperature for Dee Why on July 17th over the last 10 years is 18.73° C (65.72° F), with a low temperature of 17.32° C (63.18° F) and a high of 20.11° C (68.2° F).

Analysis and forecast for Dee Why water temperatures

The water temperature in Dee Why today is lower than the average temperature of 18.73° C (65.72° F) and the temperature on this day last year, 17th July 2024, was 17.5° C (63.5° F).

The chart and table below shows the change in water temperature in Dee Why over the last 30 days:

Date	Temperature (Celsius)	Temperature (Fahrenheit)
July 17	17.53° C	63.56° F
July 16	18.18° C	64.72° F
July 16	18.18° C	64.72° F
July 15	18.19° C	64.74° F
July 14	18.16° C	64.69° F
July 13	18.2° C	64.76° F
July 12	18.26° C	64.87° F
July 11	18.38° C	65.08° F
July 10	18.42° C	65.16° F
July 9	18.34° C	65.01° F
July 8	18.33° C	64.99° F
July 7	18.25° C	64.85° F
July 6	18.27° C	64.89° F
July 5	18.4° C	65.12° F
July 4	18.48° C	65.26° F
July 3	18.94° C	66.09° F
July 2	18.76° C	65.77° F
July 1	18.95° C	66.11° F
June 30	19.32° C	66.78° F
June 29	19.31° C	66.76° F
June 28	19.37° C	66.87° F
June 27	19.45° C	67.01° F
June 26	19.4° C	66.92° F
June 25	19.39° C	66.9° F
June 24	19.03° C	66.25° F
June 23	18.75° C	65.75° F
June 22	18.65° C	65.57° F
June 21	18.5° C	65.3° F
June 20	18.35° C	65.03° F
June 19	18.16° C	64.69° F

The actual nearshore temperatures may vary by several degrees and this can also be heavily affected by weather. Strong winds can cause cold, deep waters to replace the surface waters that had been warmed by the sun, and heavy rain can also reduce the temperature of the sea surface temperature as well.

Water temperature in Dee Why by month

The chart below shows the monthly average water temperature in Dee Why.

For more detailed information on how the sea temperature in Dee Why changes for each month of the year, choose from the months below.

January February March April May June July August September October November December

Dee Why map and nearby water temperatures