Lake Rotomahana – current water temperature and swimming conditions
This page provides information about the current water temperature at Lake Rotomahana in Bay of Plenty Region. 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 Lake Rotomahana today is 14°C.
Water Temperature in Lake Rotomahana: 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 Lake Rotomahana have been gradually cooling over the past month, with a further drop recorded during the last week.
According to our forecast, the water temperature in Lake Rotomahana will be 15.3°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 |
|---|---|---|---|
| May 6 | 13.7°C | 15.5°C | |
| May 7 | 13.7°C | 15.5°C | |
| May 8 | 16.0°C | 15.5°C | |
| May 9 | 16.0°C | 15.5°C | |
| May 10 | 14.7°C | 15.5°C | |
| May 11 | 14.7°C | 15.5°C | |
| May 12 | 14.5°C | 15.5°C | |
| May 13 | 14.2°C | 15.5°C | |
| May 14 | 13.9°C | 15.5°C | 13.9°C |
| May 15 | 15.5°C | 14.1°C | |
| May 16 | 15.5°C | 14.3°C | |
| May 17 | 15.5°C | 14.5°C | |
| May 18 | 15.5°C | 14.7°C | |
| May 19 | 15.5°C | 14.9°C | |
| May 20 | 15.5°C | 15.1°C | |
| May 21 | 15.5°C | 15.3°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 New Zealand.
Monthly Water Temperature Range (Min, Max & Average)
| Month | Today | Yesterday | A Week Ago |
|---|---|---|---|
| January | 16°C | 20°C | 24°C |
| February | 16°C | 21°C | 25°C |
| March | 17°C | 21°C | 24°C |
| April | 15°C | 18°C | 21°C |
| May | 13°C | 16°C | 18°C |
| June | 10°C | 13°C | 16°C |
| July | 9°C | 12°C | 14°C |
| August | 9°C | 12°C | 14°C |
| September | 9°C | 13°C | 16°C |
| October | 10°C | 14°C | 17°C |
| November | 12°C | 16°C | 19°C |
| December | 15°C | 19°C | 23°C |
Lake Rotomahana: Weather Forecast
May 15
May 16
May 17
May 18
May 19
May 20
Location & Local Information
Lake Rotomahana, in the Bay of Plenty Region south of Rotorua, is a geothermal lake formed and reshaped by the 1886 eruption of Mount Tarawera. Surrounded by native bush and thermal features, its water temperature is influenced by both climate and geothermal activity. In winter, surface temperatures are generally around 12–16°C, slightly warmer than some nearby lakes due to thermal inflows. During spring, the lake gradually warms to approximately 16–20°C. In summer, particularly in January and February, near-surface temperatures can reach about 20–25°C in some areas, although sections affected by geothermal vents may vary significantly. By autumn, temperatures usually ease back to between 16 and 20°C. Wind and thermal activity can create localised differences.
Swimming Conditions
Swimming is not generally recommended at Lake Rotomahana. While parts of the lake may reach comfortable temperatures in summer, geothermal vents, variable lakebed conditions and limited public shoreline access mean it is not a designated swimming destination. Boat tours operate on the lake, but recreational swimming is uncommon. Visitors seeking a water-based experience in the area are more likely to explore guided tours or nearby designated swimming lakes. Checking local guidance before entering the water is essential due to the geothermal environment.