Maranhão Reservoir — Current Water Temperature, Annual Trends and Forecast

This page provides information on the current water temperature in Maranhão Reservoir, trends, monthly ranges and the forecast for the coming days.

Covão dos Conchos Lake, Portugal © By larahcv, CC0

Current Water Temperature

21.9°C

Today

22.1°C

Yesterday

23.2°C

A Week Ago

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Water Temperature in Maranhão Reservoir today is 21.9°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

From September 16 to October 17

Table of Daily Sea Temperature Data

Date	Current	Average	Forecast
OCT 10	23.2°C	21.0°C
OCT 11	23.0°C	21.0°C
OCT 12	22.8°C	21.0°C
OCT 13	22.6°C	21.0°C
OCT 14	22.0°C	21.0°C
OCT 15	21.8°C	21.0°C
OCT 16	22.1°C	21.0°C
OCT 17	21.9°C	21.0°C
OCT 18		21.0°C	21.9°C
OCT 19		21.0°C	21.8°C
OCT 20		21.0°C	21.8°C
OCT 21		21.0°C	21.7°C
OCT 22		21.0°C	21.7°C
OCT 23		21.0°C	21.6°C
OCT 24		21.0°C	21.6°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	7°C	11°C	14°C
February	7°C	11°C	14°C
March	10°C	14°C	18°C
April	11°C	15°C	20°C
May	12°C	18°C	23°C
June	19°C	24°C	29°C
July	21°C	27°C	33°C
August	22°C	27°C	33°C
September	21°C	26°C	32°C
October	17°C	21°C	24°C
November	11°C	16°C	21°C
December	9°C	12°C	14°C

Maranhão Reservoir: Water Temperature by Location

🇵🇹 Portugal > Portalegre District

Maranhão Reservoir: Weather Forecast

October 18

° / °

overcast

rain: 23% | wind:

October 19

° / °

overcast

rain: 10% | wind:

October 20

° / °

overcast

rain: 10% | wind:

October 21

° / °

mainly clear

rain: 3% | wind:

October 22

° / °

overcast

rain: 3% | wind:

Location & Local Information

The reservoir known locally as the Albufeira da Barragem do Maranhão (Albufeira da Barragem do Maranhão) sits in the Portalegre district of Portugal and reflects the Mediterranean climate of the Alto Alentejo. Surface water temperatures vary with the seasons and with depth: in winter typical measurements are around 8–12 °C (46–54 °F), spring usually brings 12–18 °C (54–64 °F), summer often warms the surface to roughly 20–26 °C (68–79 °F), and autumn sees a gradual cooling to about 14–20 °C (57–68 °F). Shallow bays and sunny afternoons can push surface temperatures higher, while deeper or shaded sections remain markedly cooler.

Swimming is commonly practiced at the Albufeira, especially in summer when temperatures become comfortable for bathing, but whether it is officially allowed depends on local management and signage. Authorities may permit recreational swimming in designated zones, yet can also impose restrictions to protect water quality, reservoir infrastructure, or public safety—reasons include variable depths, submerged hazards, boat traffic, and occasional algal growth. Visitors should therefore follow posted rules, heed any temporary bans, and be mindful that even warm surface temperatures can mask cold layers and underwater risks.

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Frequently Asked Questions

What is the current water temperature in Maranhão Reservoir?

Water Temperature in Maranhão Reservoir today is 21.9°C.

What is the water temperature in Maranhão Reservoir during the summer months?

The water temperature in Maranhão Reservoir in summer fluctuates in the range of 19°C - 33°C.

Is it possible to swim in Maranhão Reservoir (Portugal) and what are the possibilities for this?

It is generally possible to swim in the Maranhão Reservoir in Portugal where local regulations and water-quality conditions allow, with options ranging from informal wild bathing to designated bathing areas and recreational activities like kayaking or paddleboarding where facilities exist, though you should always check local signage and authorities for restrictions, water depth, currents and safety measures before entering.