Guelph Reservoir — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Guelph Reservoir, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Guelph Reservoir today is 19°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 |
|---|---|---|---|
| JUN 23 | 16.0°C | 18.0°C | |
| JUN 24 | 16.5°C | 18.0°C | |
| JUN 25 | 16.4°C | 18.0°C | |
| JUN 26 | 16.5°C | 18.0°C | |
| JUN 27 | 16.9°C | 18.0°C | |
| JUN 28 | 17.1°C | 18.0°C | |
| JUN 29 | 17.7°C | 18.0°C | |
| JUN 30 | 18.6°C | 18.0°C | |
| JUL 1 | 23.5°C | 19.2°C | |
| JUL 2 | 23.5°C | 19.5°C | |
| JUL 3 | 23.5°C | 19.7°C | |
| JUL 4 | 23.5°C | 19.9°C | |
| JUL 5 | 23.5°C | 20.1°C | |
| JUL 6 | 23.5°C | 20.4°C | |
| JUL 7 | 23.5°C | 20.6°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 | 3°C | 6°C |
| February | 0°C | 4°C | 7°C |
| March | 0°C | 3°C | 6°C |
| April | 2°C | 8°C | 14°C |
| May | 6°C | 14°C | 22°C |
| June | 12°C | 18°C | 24°C |
| July | 20°C | 24°C | 27°C |
| August | 20°C | 25°C | 29°C |
| September | 18°C | 22°C | 25°C |
| October | 13°C | 16°C | 19°C |
| November | 3°C | 7°C | 11°C |
| December | 0°C | 5°C | 8°C |
Guelph Reservoir: Water Temperature by Location
Guelph Reservoir: Weather Forecast
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Location & Local Information
Guelph Reservoir in New York typically shows pronounced seasonal shifts in surface temperature. In winter the water often sits near freezing, roughly 32–39°F (0–4°C) and can develop stable ice cover in cold spells. Spring brings a steady warm-up, with surface values commonly in the 40–60°F (4–16°C) range as runoff and air temperatures rise. By summer the thin surface layer can reach comfortable levels for brief immersion, often about 65–78°F (18–26°C), and on hot, calm days localized spots may approach 80°F (27°C). In autumn the reservoir cools again, usually falling to roughly 45–60°F (7–16°C) as the lake mixes and loses summer heat. Deeper water remains significantly colder year-round, so temperature varies strongly with depth and location in the basin.
Swimming access at many New York reservoirs is frequently limited or prohibited, and Guelph Reservoir is often subject to those same restrictions because it functions as a managed water supply and for public-safety reasons. Restrictions are intended to protect drinking-water quality, reduce contamination risk, and minimize hazards from cold water, hidden debris, and variable currents. Even where informal wading or shoreline activity occurs, cold shock and underwater obstacles can make open-water swimming unsafe outside the warmest months, so visitors should follow posted rules and local authority guidance.