Mornington Peninsula – Water Temperature Overview

This page provides information on Mornington Peninsula locations where sea water temperature data is available, including current conditions, monthly ranges and historical records.

Current Water Temperature

18.9°C

minimum

19.3°C

average

20.2°C

maximum

The current water temperature in the Mornington Peninsula today is within the range of 19-20°C. Thus, the average water temperature is about 19°C. Water in this range feels cool but still manageable for many swimmers. Short to moderate swims are comfortable, especially in warm weather. Some people may prefer a wetsuit for longer stays, particularly when swimming actively or outside peak summer conditions.

It’s important to note that these swimming tips and recommendations apply only in settled weather. When air temperatures drop below 20°C — and sometimes even below 25°C — swimming can feel uncomfortable, even when water temperatures are relatively high.

Sea Temperature Trends

Water Temperature Over the Last 60 Days

Over the past month, the sea water temperature has remained largely unchanged. Overall, the sea water temperature is within the range expected based on historical data for this month.

Water Temperature and Swimming Conditions by Month

Month	Min	Avg	Max
January	15°C	19°C	23°C
February	17°C	20°C	22°C
March	17°C	20°C	22°C
April	15°C	18°C	20°C
May	14°C	16°C	18°C
June	11°C	14°C	16°C
July	10°C	13°C	15°C
August	10°C	12°C	14°C
September	11°C	13°C	15°C
October	11°C	14°C	17°C
November	13°C	16°C	19°C
December	15°C	18°C	21°C

The Mornington Peninsula sits between Port Phillip Bay and the open waters of Bass Strait, giving the area a mix of sheltered and exposed coastal conditions. Sea water temperatures vary noticeably through the year and are generally cooler than in northern Australia. During summer, water temperatures typically range from about 17°C to 20°C, with the warmest conditions usually found along the bay side. Autumn often remains comfortable, with temperatures around 15–18°C before cooling further in winter. In winter, sea water temperatures commonly fall to around 12–14°C, feeling quite cold on entry and limiting time in the water for most people. Spring brings a gradual increase, with temperatures rising back toward 14–17°C as summer approaches.

Swimming Conditions

Swimming is allowed across the Mornington Peninsula and is popular, particularly at bay beaches where conditions are calmer and water temperatures are slightly higher. Summer is the main swimming season, when warmer water and milder weather allow for more comfortable swims, especially for families and casual beachgoers. On the open ocean side facing Bass Strait, water tends to be cooler and conditions more energetic, attracting surfers rather than casual swimmers. In cooler months, swimming continues among locals, surfers and open-water swimmers, though wetsuits are commonly used due to low water temperatures. With a wide choice of sheltered bays, ocean beaches and coastal facilities, the Mornington Peninsula offers varied swimming opportunities, best enjoyed during the warmer months when sea conditions and temperatures are more favourable.