Manly Reservoir – current water temperature and swimming conditions
This page provides information about the current water temperature at Manly Reservoir in New South Wales. Here you can view recent temperature trends on a 30-day chart, check typical monthly water temperature ranges, and compare today’s reading with historical averages for this date. A 7-day water temperature forecast, local weather conditions, and an overview of swimming suitability are also included.
Current Water Temperature
The water temperature in Manly Reservoir today is 13°C.
Water Temperature in Manly Reservoir: Daily Trends, Historical Records, and Forecast
⚠️ Lake temperatures between 10 and 15°C are cold but can be manageable for short swims on sunny, warm days. Shallow areas may feel slightly warmer, while deeper sections remain cold and slow to warm up. Most swimmers keep sessions brief, and wetsuits are often used for comfort. Wind and cooler air temperatures can quickly reduce how pleasant the swim feels.
Water Temperature Over the Last 30 Days
Water temperatures in Manly Reservoirfell over the past month, but have levelled out during the last week.
According to our forecast, the water temperature in Manly Reservoir will be 11.3°C in the next 7 days. See the table below for daily data for the upcoming week.
Table of Daily Water Temperature Data
| Date | Current | Average | Forecast |
|---|---|---|---|
| Jun 13 | 13.0°C | 11.0°C | |
| Jun 14 | 13.0°C | 11.0°C | |
| Jun 15 | 13.0°C | 11.0°C | |
| Jun 16 | 13.0°C | 11.0°C | |
| Jun 17 | 13.0°C | 11.0°C | |
| Jun 18 | 13.0°C | 11.0°C | |
| Jun 19 | 13.0°C | 11.0°C | |
| Jun 20 | 13.0°C | 11.0°C | |
| Jun 21 | 13.0°C | 11.0°C | 13.0°C |
| Jun 22 | 11.0°C | 12.8°C | |
| Jun 23 | 11.0°C | 12.5°C | |
| Jun 24 | 11.0°C | 12.3°C | |
| Jun 25 | 11.0°C | 12.0°C | |
| Jun 26 | 11.0°C | 11.8°C | |
| Jun 27 | 11.0°C | 11.5°C | |
| Jun 28 | 11.0°C | 11.3°C |
* Current - Actual water temperature value
** Average - Average water temperature on this day in recent years
*** Forecast - Our water temperature forecast
Actual lake water temperatures may differ from the reported values by several degrees, particularly during periods of strong winds or rapid weather changes. Wind can mix surface and deeper layers in a lake, bringing cooler water to the surface, while shallow areas may warm more quickly under direct sunlight. Air temperature, sunshine, and cloud cover strongly influence how quickly a lake heats up or cools down. These factors can lead to noticeable temperature variations across different parts of the lake.
Our forecast is based on a proprietary mathematical model that considers real-time lake temperature observations, historical trends, seasonal cycles, wind strength and direction, and region-specific air temperature. To enhance accuracy, we also incorporate data from nearby monitored locations and comparable lakes within Australia.
Monthly Water Temperature Range (Min, Max & Average)
| Month | Today | Yesterday | A Week Ago |
|---|---|---|---|
| January | 15°C | 23°C | 26°C |
| February | 20°C | 23°C | 26°C |
| March | 19°C | 21°C | 24°C |
| April | 16°C | 18°C | 20°C |
| May | 11°C | 14°C | 17°C |
| June | 8°C | 11°C | 13°C |
| July | 8°C | 10°C | 13°C |
| August | 8°C | 11°C | 13°C |
| September | 12°C | 14°C | 17°C |
| October | 15°C | 17°C | 19°C |
| November | 18°C | 20°C | 24°C |
| December | 13°C | 23°C | 25°C |
Location & Local Information
Manly Reservoir sits just inland from the Northern Beaches and is surrounded by bushland, giving it a quiet, sheltered feel despite being close to suburban Sydney. Water temperature in the reservoir reflects the local coastal climate but remains relatively cool throughout the year. In summer, surface temperatures usually reach around 20–24°C, which can feel refreshing rather than warm, especially after cooler nights. Spring and autumn typically sit between 16–20°C, while winter sees temperatures drop to about 12–15°C. The depth of the reservoir means it warms and cools slowly, so sudden temperature changes are uncommon.
Swimming Conditions
Swimming in Manly Reservoir is not allowed. The lake is managed as part of Sydney’s drinking water supply system, and strict rules are in place to protect water quality. Activities involving direct contact with the water, including swimming, are prohibited regardless of season or temperature. Even in summer, when the water may appear suitable for a dip, access to the water is restricted and closely monitored. In addition, steep banks, variable depths, and limited safe entry points would make swimming unsafe even without the regulations. Overall, Manly Reservoir is best enjoyed for walking, cycling, and appreciating the surrounding bushland, with its water temperatures noted more out of interest than for recreation, as swimming is not permitted.