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 10°C.
Water Temperature in Lake Rotomahana: Daily Trends, Historical Records, and Forecast
❌ Lake water below 10°C is extremely cold and generally unsuitable for swimming for most people. Even during warm weather, deep lakes retain cold water, making entry uncomfortable and limiting time in the water. Swimming at this temperature is usually limited to quick dips or cold-water enthusiasts. Cool air temperatures or cloudy conditions can make lake swimming particularly harsh.
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 12.0°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 |
|---|---|---|---|
| Aug 19 | 13.9°C | 12.4°C | |
| Aug 20 | 14.0°C | 12.4°C | |
| Aug 21 | 13.7°C | 12.4°C | |
| Aug 22 | 13.6°C | 12.4°C | |
| Aug 23 | 13.7°C | 12.4°C | |
| Aug 24 | 13.8°C | 12.4°C | |
| Aug 25 | 9.5°C | 12.4°C | |
| Aug 26 | 9.5°C | 12.4°C | |
| Aug 27 | 9.5°C | 12.4°C | 9.5°C |
| Aug 28 | 12.4°C | 9.9°C | |
| Aug 29 | 12.4°C | 10.2°C | |
| Aug 30 | 12.4°C | 10.6°C | |
| Aug 31 | 12.4°C | 11.0°C | |
| Sep 1 | 12.4°C | 11.3°C | |
| Sep 2 | 12.4°C | 11.7°C | |
| Sep 3 | 12.4°C | 12.0°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
August 28
August 29
August 30
August 31
September 1
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.