What was the coldest temperature recorded in Singapore?
What is Singapore's climate like?
What are Sumatras?
What are the various sources of meteorological data?
How do we forecast the weather?
What are the uses of climate data?
What is the reference level of the tide measurement?
Tsunami FAQ
What is a tsunami?
How fast can a tsunami travel and how soon could it impact on coastal areas after it has formed?
How can we differentiate a tsunami wave from normal ocean waves?
What time of the day are occurrences of tsunamis more likely?
How are tsunamis detected?
Could Singapore be affected by a tsunami?
What should I do if I got caught in a tsunami event?
Where can additional information on tsunamis be found?
What is the coldest temperature recorded in Singapore?
The lowest minimum temperature ever recorded in the month of December is 20.6 deg C ( on 2 Dec 1964), while the lowest temperature ever recorded (since record began in 1929) is 19.4 deg C (on 31 Jan 1934).
Cool weather over Singapore are caused by the following conditions :
i ) periods of cloudy to overcast weather accompanied by rain which blocks out the heat from the sun
ii ) season and prevailing wind
Usually the Northeast Monsoon months of December and January are the cooler months of the year with average highest temperature of 29..9 deg C as compared to 31.5 deg C in the months of April and May, and with average minimum temperature of 23.1 deg C in Dec and Jan as compared to 24.3 deg C in the months of April and May. The early part of the Northeast monsoon (months of December and January) is usually characterised by generally cloudy and windy conditions with rain periods lasting for 2 to 3 days at a stretch.
The cool north-east winds which blow over Singapore during this time of the year originate from the cold winter conditions of the interior of the Asian continent. .
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What is Singapore's climate like?
Singapore's average annual rainfall is 2357.8 mm.
Climatologically speaking, February falls in the latter half of the Northeast Monsoon Season and is a relatively dry month. In fact, it has only 11 raindays as compared to 20 days in December, which lies in the wet part of the Northeast Monsoon. Hence, the drier weather in February is expected. March is the last of the Northeast Monsoon months. There is a tendency for the rainfall to slightly increase in March. This results from a gradual increase in shower activity arising from connective heating in the afternoon and early evening over the island.
However, despite the above observations based on long-term records, from year to year there could be variations in the degree of dryness due to annual climatic fluctuations.
In general, dry weather is the result of lack of convection or stable atmosphere which prevents the devleopment of rain-bearing clouds. Vertical uplifting of the air is weak when the atmosphere is stable or this could be cause by descending air over a large area ? as is often observed during periods of widespread haze in SW Monsoon months. Winds blowing from dry regions are usually lacking insufficient moisture thus preventing clouds from forming. Strong winds aloft sometimes inhibit the vertical development of rain-bearing clouds.
Singapore has two main seasons, the Northeast Monsoon (December to March) and the Southwest Monsoon season (May to September), separated by two relatively shorter inter-monsoon periods. Although there are no distinct wet or dry periods, the mean monthly rainfall shows drier weather conditions from May to July and wetter conditions in the months from November to January. . February is also a relatively dry month. The beginning and end of the monsoons are usually not very well-defined. Hence, from year to year, there could be slight delay in the beginning or end of a monsoon period. This probably accounts for the monthly rainfall anomaly experienced from year to year.
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What are Sumatras?
Sumatras are line of thunderstorms which usually occur during the Southwest Monsoon season from May to October each year. These squalls develop at night over Sumatra or the Malacca Straits and move east towards Singapore and the west coast of Peninsular Malaysia during the pre-dawn and early morning. They are often characterised by sudden onset of strong gusty surface winds and heavy rain lasting from 1 to 2 hours as they move across the island. Maximum gusts of up to 50 knots have been recorded during the passage of a Sumatra squall.
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What are the various sources of meteorological data?
Meteorological data are obtained from various sources such as through a network of weather observational stations located at various parts on the island. These observational stations include synoptic stations, weather radars, weather satellites, upper air observing stations and lightning sensors to name a few. Other sources include an exchanged of meteorological data with other national meteorological centres in the region through the Global Telecommunication System (GTS) of the World Meteorological Organisation(WMO). The Singapore National Meteorological Center is linked to counterparts in the neighbouring countries by medium to high-speed telecommunication circuits which form part of the Regional Telecommunications Network of the GTS.
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How do we forecast the weather?
Many factors are taken into consideration when a forecast is to be made. One requirement for any forecast is the availability of meteorological data which must be reliable, accurate and regular. With the numerous meteorological data we analyse weather patterns. With the analysed weather charts together with numerical weather prediction products, satellite images, knowledge of the climatology of the area and experience, a forecast is made. Numerical weather prediction products are computer generated forecast models. These run on supercomputers and they provide predictions of on atmospheric vairables such as rainfall, pressure, temperature, wind etc..
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What are climate data used for?
Climate data are used in various industries such as the construction industry, in legal firms, marine industry and many more. Some uses of climate data are given in our Climatological Services webpage
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What is the reference level of the tide measurement?
Tides are measured relative to a reference point known as 'Chart Datum'. Chart Datum is the lowest water level recorded over a fixed period (usually 18 years) at a particular point.
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What is a tsunami?
A tsunami is a series of enormous waves formed in the sea or near the coast and is generated by violent undersea disturbances such as earthquake- induced movement of the ocean floor, landslides and underwater volcanic eruptions. Most tsunamis are caused by earthquakes in the sea that induce movements in the sea floor. From the area where the tsunami originates, waves travel outwards in all directions and can travel great distances. In deep water the tsunami wave is not noticeable, but when it approaches the shore it increases in height. All tsunami are potentially dangerous and can be extremely violent and damaging when they hit the shore.
Not all earthquakes, however, will produce tsunamis. Normally, it would require an earthquake with a magnitude exceeding 7.5 on the Richter scale to produce a destructive tsunami.
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How fast can a tsunami travel and how soon could it impact on coastal areas after it has formed?
In deep ocean, tsunami waves can travel at speed exceeding 800 kilometers per hour and a wave height of less than a meter. As they reach the shallow waters of the coast, the waves slow down and the water can pile up into a wall of destruction tens of meters or more in height. The effects can be amplified where a bay, harbour or lagoon funnels the wave as it moves inland. Large tsunamis have been known to rise over 30 meters. Even a tsunami 3-6 meters high can be very destructive and cause many deaths and injuries
Tsunamis can reach coastlines more than 1000 km away within in a few hours
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How can we differentiate a tsunami wave from normal ocean waves?
Tsunami waves are distinguish from ocean waves by their great length between wave crests, often exceeding 100 kilometers or more in the deep ocean and by the time between these crests, ranging from 10 minutes to an hour. Often the first wave may not be the largest. The danger from a tsunami can last for several hours after the arrival of the first wave.
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What time of the day are occurrences of tsunamis more likely?
Tsunami can occur at any time, day or night.
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How are tsunamis detected?
Earthquake monitors and sea level gauges that detect earthquakes and abnormal changes in sea level could be used to detect and provide early warning of tsunamis. Currently the Pacific Tsunami Warning System operates from Hawaii to issue warnings for potential tsunamis in the Pacific Ocean. If a tsunami is detected, coastal areas lying in the predicted path are warned. There is currently no similar system for detection and warning of potential tsunamis in the Indian Ocean.
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Could Singapore be affected by a tsunami?
Earthquakes in our region are more prone to occur along the major fault-lines off the outer coasts of Sumatra, Java and the Philippines. Due to its geographic location, Singapore is sheltered by the Indonesian Archipelago in the west and south and the Philippines in the east. Therefore it is very unlikely for Singapore to be directly affected by a tsunami.
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What should I do if I got caught in a tsunami event?
If you are at the beach or near the ocean and you feel the earth shake, move immediately to a higher ground. Do not wait for a tsunami warning to be given.
In some cases the sudden draw down of sea level resulting in receding of the shoreline, sometimes by a kilometer or more is a sign of preceding or in between crests of tsunami waves. Head for the high ground as quickly as possible. Do not stay at or approach the beach to investigate.
If you are advised to evacuate, do so immediately.
Stay away from the area until local authorities say it is safe. Do not be fooled into thinking the danger is over after a single wave ? a tsunami is not a single wave but a series of waves that can vary in size.
Do not go to the shoreline to watch for a tsunami. When you can see the wave, it is often too late to escape.
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Where can additional information on tsunamis be found?
Pacific Tsunami Warning Centre
http://www.prh.noaa.gov/ptwc/abouttsunamis.htm
National Oceanic and Atmospheric Adminstration
http://www.noaa.gov/tsunamis.html
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