Lake Winnipesaukee — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Lake Winnipesaukee, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Lake Winnipesaukee today is 19.1°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
⚠️ As of today, the minimum water temperature ranges from 65°F (18°C) to 68°F (20°C). This is already quite warm water, which is ideal for most people. Swimming becomes comfortable, and prolonged stays in the water do not cause discomfort. This temperature is perfect for family trips and for those who prefer warmer water. It is also comfortable for water sports such as surfing or swimming. It is important to note that these swimming tips and recommendations apply only in good weather. When the air temperature is below 68°F (20°C), and sometimes even below 77°F (25°C), swimming can be unpleasant even with relatively high water temperatures.
Water Temperature Chart Over the Last 30 Days
Table of Daily Sea Temperature Data
| Date | Current | Average | Forecast |
|---|---|---|---|
| SEP 14 | 20.1°C | 21.7°C | |
| SEP 15 | 20.3°C | 21.7°C | |
| SEP 16 | 20.2°C | 21.7°C | |
| SEP 17 | 18.9°C | 21.7°C | |
| SEP 18 | 18.9°C | 21.7°C | |
| SEP 19 | 20.1°C | 21.7°C | |
| SEP 20 | 19.9°C | 21.7°C | |
| SEP 21 | 19.1°C | 21.7°C | |
| SEP 22 | 21.7°C | 19.2°C | |
| SEP 23 | 21.7°C | 19.4°C | |
| SEP 24 | 21.7°C | 19.5°C | |
| SEP 25 | 21.7°C | 19.6°C | |
| SEP 26 | 21.7°C | 19.8°C | |
| SEP 27 | 21.7°C | 19.9°C | |
| SEP 28 | 21.7°C | 20.0°C |
* Current - Actual water temperature value
** Average - Average water temperature on this day in recent years
*** Forecast - Our water temperature forecast
Actual nearshore water temperatures may fluctuate by several degrees from the reported values, especially following heavy rainfall or extended periods of strong winds. Certain wind patterns can cause colder, deeper waters to rise and replace the sun-warmed surface water, leading to noticeable variations.
Our forecast is based on a proprietary mathematical model that considers real-time water temperature changes, historical trends, key weather patterns, wind strength and direction, and air temperature specific to each region. Additionally, we incorporate data from other resorts to enhance accuracy.
Monthly Water Temperature Range (Min, Max & Average)
| Month | Min | Avg | Max |
|---|---|---|---|
| January | 0°C | 8°C | 15°C |
| February | 0°C | 7°C | 13°C |
| March | 0°C | 7°C | 13°C |
| April | 2°C | 10°C | 16°C |
| May | 9°C | 14°C | 19°C |
| June | 13°C | 17°C | 22°C |
| July | 19°C | 25°C | 31°C |
| August | 21°C | 23°C | 26°C |
| September | 19°C | 22°C | 24°C |
| October | 12°C | 16°C | 19°C |
| November | 4°C | 8°C | 12°C |
| December | 1°C | 5°C | 7°C |
Lake Winnipesaukee: Water Temperature by Location
Lake Winnipesaukee: Weather Forecast
September 21
September 22
September 23
September 24
September 25
Location & Local Information
Lake Winnipesaukee’s surface temperature varies markedly by season. In summer the lake commonly warms into the high 60s to mid 70s °F (about 20–24 °C) and during hot spells can reach the upper 70s to low 80s °F (25–28 °C) at the surface. Spring and early summer are cooler, with surface readings often in the 40s to 60s °F (4–16 °C) as the water stratifies, while autumn brings a steady decline back through the 50s into the 40s °F (10–4 °C). In winter the lake freezes in many areas and under-ice temperatures gravitate toward the temperature of maximum density near 39 °F (4 °C); surface ice and slushy conditions are at or below 32 °F (0 °C).
Swimming is generally allowed and popular in warmer months because public beaches, parks and private docks provide access and summer temperatures are comfortable for short swims. However, users should be mindful of cold-water risk outside the warmest weeks, heavy boat traffic in busy areas, and occasional water-quality advisories for cyanobacteria or contamination that can prompt temporary closures. Lifeguards are present at some municipal beaches, but swimmers should check local advisories and exercise caution, since deep, cold water and sudden temperature changes raise risks of cold shock and hypothermia.