Hempstead Lake — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Hempstead Lake, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Hempstead Lake today is 22.1°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
✅ As of today, the minimum water temperature ranges from 68°F (20°C) to 74°F (23°C). The water is warm and pleasant for swimming, and in this range, one can stay in the water for extended periods without the risk of hypothermia. This is the ideal temperature for relaxation, swimming, and water sports. Families with children, as well as outdoor enthusiasts, will enjoy swimming and time spent in the water. For most people, this is the optimal temperature for a comfortable beach experience. 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 |
|---|---|---|---|
| JUN 3 | 17.8°C | 20.9°C | |
| JUN 4 | 20.0°C | 20.9°C | |
| JUN 5 | 20.5°C | 20.9°C | |
| JUN 6 | 21.0°C | 20.9°C | |
| JUN 7 | 21.5°C | 20.9°C | |
| JUN 8 | 21.5°C | 20.9°C | |
| JUN 10 | 22.1°C | 20.9°C | |
| JUN 11 | 20.9°C | 22.0°C | |
| JUN 12 | 20.9°C | 22.0°C | |
| JUN 13 | 20.9°C | 21.9°C | |
| JUN 14 | 20.9°C | 21.9°C | |
| JUN 15 | 20.9°C | 21.8°C | |
| JUN 16 | 20.9°C | 21.7°C | |
| JUN 17 | 20.9°C | 21.7°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 | 2°C | 4°C |
| February | 0°C | 2°C | 4°C |
| March | 0°C | 5°C | 10°C |
| April | 7°C | 13°C | 18°C |
| May | 11°C | 16°C | 22°C |
| June | 17°C | 21°C | 24°C |
| July | 23°C | 26°C | 29°C |
| August | 22°C | 25°C | 28°C |
| September | 19°C | 23°C | 27°C |
| October | 13°C | 17°C | 20°C |
| November | 6°C | 10°C | 13°C |
| December | 1°C | 6°C | 9°C |
Hempstead Lake: Water Temperature by Location
Hempstead Lake: Weather Forecast
June 9
June 10
June 11
June 12
Location & Local Information
Hempstead Lake, in Hempstead Lake State Park on Long Island, is a relatively shallow freshwater body so its surface temperature moves with the seasons and local weather. In winter the water typically sits near freezing, about 32–40°F (0–4°C), and can ice over during prolonged cold spells. Spring brings a steady rise as runoff and warming air lift temperatures into the 40–60°F range (4–16°C). By summer, especially in July and August, surface temperatures commonly reach the upper 60s to low 80s Fahrenheit, roughly 20–28°C in the warmest, sun-exposed areas; deeper or shaded sections remain a few degrees cooler. In autumn the lake cools again, often falling to about 50–65°F (10–18°C) as air temperatures decline. Local wind, depth and sunlight cause considerable short-term variability.
Swimming is generally not a sanctioned activity at Hempstead Lake because the park lacks a designated supervised beach and lifeguard service, and water access is managed primarily for fishing, boating and passive recreation. Posted park rules and safety considerations—such as variable depths, boat traffic, and occasional water-quality issues—mean visitors should assume open-water swimming is discouraged or prohibited unless a specific, staffed swimming area is provided by park authorities. Always check current park notices before entering the water.