CLIMATE (Part I)
3.1 Introduction
3.2 Climate in the Data Dictionary
3.3 Climate Data
3.3.1 Temperature Distribution
3.3.2 Rainfall Distribution
3.3.3 Wind
CLIMATE (Part II) (Wind Data Tables & Graphs)
CLIMATE (Part III)
3.3.4 Relative Humidity
3.3.5 Sunshine
3.3.6 Evaporation
3.3.7 Flood and Drought Prone Areas
3.3.8 Haze
3.4 Information Issues
3.4.1 Issues related to parameters
3.5 ICZM Issues Arising
3.5.1 Issues related to geographical distribution (spatial)
3.5.2 Issues related to seasonal variability (temporal)
3.5.3 Issues related to annual variability (trend)

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CLIMATE (Part I)

3.1  Introduction

Sabah experiences a typical equatorial climate, with constant temperature, considerable amount of rain and high humidity. The two prevailing monsoons in Sabah, which characterise the climate in this region are the Northeast Monsoon and the Southwest Monsoon. Northeast Monsoon predominates the months between November and March, whereas the Southwest Monsoon prevails during the months of May to September. There are also two successive inter-monsoons; April to May and September to October.

The Meteorological Department in Sabah operates in five meteorological stations, namely, Kota Kinabalu, Sandakan, Kudat, Tawau and Labuan. However, other government departments and private companies are also monitoring climate conditions in Sabah, depending on the relevant data needed by the individual departments or companies.

Table 6: Location of Meteorological Stations (Latitude and Longitude) in Sabah

StationLatitudeLongitude
Kota Kinabalu05 - 56 - N116 - 03 - E
Sandakan05 - 54 - N118 - 04 - E
Kudat06 - 55 - N116 - 50 - E
Tawau04 - 16 - N117 - 53 - E
Labuan05 - 18 - N115 - 15 - E

Source: Meteorological Department, Sabah

3.2  Climate in the Data Dictionary

Figure 6: Climate in the Data Dictionary

Eight main groups of parameters in the climate sector required for the ICZM project have been identified. They include temperature distribution, rainfall distribution, wind, relative humidity, sunshine and solar radiation, evaporation, flood and drought prone areas and haze. For each parameter, information such as its definition, source of data and its availability are available in the data dictionary. The availability of data for each parameter is vital for the analyses of the effects of climate conditions in Sabah. Accordingly, the results of the analyses can be used in hazard management (flooding and drought) and also in the tourism industry.

Figure 6 shows the climate indexes in the ICZM Data Dictionary.


3.3  Climate Data

3.3.1  Temperature Distribution

During normal periods, temperature distribution in Sabah is constant and fairly high throughout the year. However, occurrences such as El Niņo32 and La Niņa33 would affect the temperature as these two events produce extreme climatic conditions.

Seasonal Variability: Generally, there was a slight decrease of temperature from July until the end of the year within the 8-year period (Figure 7). The average of the monthly mean temperature values from 1990 to 1997 ranged between 26oC and 28oC in all the stations in Sabah. The standard deviation34 of the average of monthly mean temperature within the 8-year period was less than 1oC (Table 7). Therefore, the temperature variation within a year was small. Relatively, the months between March and July were recorded as the period in which temperatures were the highest (Figure 7). This period coincided with the less rainy Southwest Monsoon that usually prevails between May and September each year.

Geographical Variability: Kota Kinabalu, Sandakan, Kudat and Labuan recorded relatively high and similar temperatures (Figure 7). However, Tawau registered relatively lower temperatures within the period of data. The maximum average of monthly mean temperature recorded within the 8-year period was about 28.4oC (May) in Kudat. Tawau recorded the lowest average of monthly mean temperature of about 26oC (January) (Table 7). Labuan, in particular, registered relatively high temperature all year long compared to the four stations.

Annual Variability: Table 8 shows the average and standard deviation of the annual mean temperature from 1990 to 1997. The temperature variation during the period was small. The trend of temperature in Sabah could only be analysed if historical annual temperature data for a few decades are available.

Figure 7: Average of Monthly Mean Temperature (oC) for Kota Kinabalu, Sandakan, Kudat, Tawau and Labuan (1990 – 1997)

Table 7: Average of Monthly Mean Temperature (oC) for Kota Kinabalu, Sandakan, Kudat, Tawau and Labuan (1990-1997)

MONTH

KOTA KINABALU

SANDAKAN

KUDAT

TAWAU

LABUAN

January

26.5

26.6

26.7

26.0

27.0

February

26.7

26.8

26.9

26.2

27.0

March

27.3

27.5

27.6

26.7

27.7

April

28.0

28.1

28.2

27.1

28.2

May

28.0

28.3

28.4

27.2

28.3

June

27.8

28.1

27.9

26.9

28.1

July

27.5

27.7

27.4

26.6

27.7

August

27.6

27.7

27.5

26.6

28.0

September

27.4

27.5

27.4

26.7

27.7

October

27.1

27.4

27.1

26.8

27.4

November

27.0

27.2

26.9

26.7

27.5

December

26.9

26.8

26.8

26.3

27.4

Average

27.3

27.5

27.4

26.7

27.7

Standard Deviation

0.5

0.5

0.5

0.3

0.4

Source: Meteorological Department, Sabah

Table 8: Average and Standard Deviation of Annual Mean Temperature (oC) for Kota Kinabalu, Sandakan, Kudat, Tawau and Labuan

STATION19901991199219931994199519961997
AverageAverageAverageAverageAverageAverageAverageAverage
KOTA KINABALU27.327.327.427.227.327.327.227.6
SANDAKAN27.727.527.627.327.327.527.327.6
KUDAT27.627.427.627.227.327.327.227.7
TAWAU26.626.726.526.626.626.726.626.9
LABUAN27.827.827.727.527.727.627.427.8
19901991199219931994199519961997
Standard DeviationStandard DeviationStandard DeviationStandard DeviationStandard DeviationStandard DeviationStandard DeviationStandard Deviation
KOTA KINABALU0.50.60.60.60.40.50.70.7
SANDAKAN0.50.50.80.50.40.50.80.8
KUDAT0.50.70.70.70.30.60.80.7
TAWAU0.50.30.50.50.30.30.50.6
LABUAN0.50.50.60.60.30.60.70.6

Source: Meteorological Department, Sabah

3.3.2  Rainfall Distribution

Sabah receives a substantial amount of rainfall as recorded at the meteorological stations. This region is greatly influenced by two monsoon seasons; Northeast Monsoon (November to March) and Southwest Monsoon (May to September). The former brings a considerable amount of rain in most parts of Sabah, whilst the latter, a drier period.

Seasonal Variability: Figure 8 shows that the rainfall distribution throughout the year within the 8-year period was not constant. The relatively wetter months were between December and January. This coincided with the Northeast Monsoon that usually prevails between November and March. Figure 10 and Table 11 show that as with the rainfall distribution, the average values of the monthly mean raindays were also not regularly distributed. The months from September and January experienced more days with rain, than other months. This period also corresponded to the period of the Northeast Monsoon.

Geographical Variability: Figure 8 and Table 9 shows that most of the stations received a similar and substantial amount of rain, except for Tawau. The variation of rainfall distribution in Tawau was less compared to the rest of the stations. Table 11 shows that all the stations, except Tawau, experienced a high variability of raindays distribution.

Annual Variability: Figure 9 and Table 10 indicate that from 1990 to 1997, there was a high annual variability of rainfall distribution. Sandakan in particular, experienced more rainfall in 1994 and 1996. Relatively more raindays were experienced at the five stations between the years 1994 and 1996 (Figure 11).

Figure 8: Average of Monthly Mean Rainfall (mm per month) for Kota Kinabalu, Sandakan, Kudat, Tawau and Labuan (1990 – 1997)

Table 9: Average and Standard Deviation of Monthly Mean Rainfall (mm per month) for Kota Kinabalu, Sandakan, Kudat, Tawau and Labuan (1990 – 1997)

MONTHKOTA KINABALUSANDAKANKUDATTAWAULABUAN
January61.9364.6282.896.7104.8
February54.8281.7139.1106.795.0
March35.9151.288.498.951.8
April128.6120.168.583.3209.4
May209.7137.473.1133.5277.8
June280.7164.6122.9166.6243.4
July306.3202.5105.0239.5287.1
August260.6267.793.7211.4274.1
September276.5247.187.4161.1292.6
October343.9262.9179.6141.8405.4
November277.7342.8291.3148.3311.4
December232.0517.9396.6169.7245.6
Average205.7255.0160.7146.4233.2
Standard Deviation107.4114.3106.347.2102.3

Source: Meteorological Department, Sabah

Table 10: Average and Standard Deviation of Annual Monthly Mean Rainfall (mm) for Kota Kinabalu, Sandakan, Kudat, Tawau and Labuan.

STATION19901991199219931994199519961997
AverageAverageAverageAverageAverageAverageAverageAverage
KOTA KINABALU209.6180.5186.9221.2188.9266.2232.3160.1
SANDAKAN211.3247.9205.6266.8356.6183.5340.8227.8
KUDAT130.6156.7115.6142.1205.6178.8212.3143.8
TAWAU167.4139.2101.8152.3168.8182.1164.196.0
LABUAN175.6201.2224.1236.9184.8325.4284.7232.9
19901991199219931994199519961997
Standard DeviationStandard DeviationStandard DeviationStandard DeviationStandard DeviationStandard DeviationStandard DeviationStandard Deviation
KOTA KINABALU175.0143.3169.5230.9128.8192.8111.2117.4
SANDAKAN236.7148.5175.8163.5137.685.2236.2183.7
KUDAT123.9131.8122.4131.0143.6155.9217.2116.9
TAWAU103.682.986.084.880.777.1112.0100.6
LABUAN115.5145.9190.1185.197.1196.4160.4125.5

Source: Meteorological Department, Sabah

Figure 9: Annual Average of Monthly Mean Rainfall (mm per month) for Kota Kinabalu, Sandakan, Kudat, Tawau and Labuan

Figure 10: Average of Monthly Mean Raindays for Kota Kinabalu, Sandakan, Kudat, Tawau and Labuan (1990 – 1997)

Table 11: Average of Monthly Mean Raindays for Kota Kinabalu, Sandakan, Kudat, Tawau and Labuan (1990 – 1997)

MONTHKOTA KINABALUSANDAKANKUDATTAWAULABUAN
January8.620.017.811.99.1
February8.814.010.912.98.9
March7.39.58.410.68.4
April11.18.86.89.815.9
May16.011.08.415.117.1
June15.411.812.013.417.1
July15.314.111.517.316.0
August15.115.312.614.114.6
September15.814.813.013.518.5
October20.517.917.413.420.9
November19.421.021.815.020.6
December14.622.021.117.816.9
Average14.015.013.513.715.3
Standard Deviation4.24.45.02.44.3

Source: Meteorological Department, Sabah

Figure 11: Annual Average of Monthly Mean Raindays for Kota Kinabalu, Sandakan, Kudat, Tawau and Labuan

Table 12: Average and Standard Deviation of the Annual Monthly Mean Raindays for Kota Kinabalu, Sandakan, Kudat, Tawau and Labuan

19901991199219931994199519961997
AverageAverageAverageAverageAverageAverageAverageAverage
KOTA KINABALU11.813.512.814.214.415.816.812.8
SANDAKAN13.315.313.413.817.715.816.614.3
KUDAT12.813.811.213.315.913.914.812.0
TAWAU14.612.711.112.215.116.316.811.1
LABUAN12.913.814.016.115.516.918.614.9
19901991199219931994199519961997
Standard DeviationStandard DeviationStandard DeviationStandard DeviationStandard DeviationStandard DeviationStandard DeviationStandard Deviation
KOTA KINABALU5.35.97.97.03.77.35.26.1
SANDAKAN5.55.47.85.54.45.45.66.2
KUDAT5.26.37.06.65.37.16.05.8
TAWAU4.34.85.54.13.23.94.35.2
LABUAN5.05.67.96.73.67.45.95.3

Source: Meteorological Department, Sabah

3.3.3  Wind

Wind speed intervals in Sabah are classified in seven categories as shown in Table 13. The table also shows the Beaufort Scale devised in 1805 by Sir Francis Beaufort to indicate the scale and conditions of wind speeds. Beaufort Scale is commonly used by people involved in the maritime sector. However, it is not used by the Meteorological Department in Sabah. A comparison was carried out between the Beaufort Scale and the wind speed intervals in Sabah because it is relatively easier to comprehend observational type of explanation than a numerical explanation of wind speed reading. For example, a person with no meteorological background would find it easier to understand land condition of ‘moderate breeze: moves thin branches, raises dust and paper’ rather than wind speed reading of 6 m/s. The system of wind speed intervals used in Sabah conforms to the Beaufort Scale until Force 6. Wind speeds exceeding 10.7 m/s (after Force 6) are categorised in one category. This could be due to the fact that Sabah seldom experiences extreme wind conditions to require specific classification of wind speeds above 10.7 m/s. There are four main periods in which the wind data35 were registered in Labuan, Kota Kinabalu, Kudat, Sandakan and Tawau. Period I, II, III and IV are January, May-September, October and November-March respectively. Figure 12 presents graphs showing directions of wind speed from Period I to IV. One must note that Figure 12 should not be confused with wind roses as the aim of presenting the graphs is to show a general trend of wind directions within the specific months and periods using wind data in Table 14.

Seasonal Variability: As shown in Period I in (Figure 12), the prevailing wind in January for Sabah within the period of data were from the north and east directions. The north and east influence is due to the prevailing Northeast Monsoon that usually takes place between November and March. The maximum reading observed from the five meteorological stations ranged between 5.5 and 7.9 m/s (Table 14). The range of wind speeds gives moderate breeze condition (Table 13).

During the Southwest Monsoon from May to September (Period II in Figure 12) in Sabah, the dominant wind blew from the south and west. The prevailing wind speed ranged from 0.3 to 3.3 m/s. Wind conditions during the wind speed interval are between light air and light breeze (Table 13). The intensity of wind speed between 8.0 and 10.7 m/s was experienced in a low scale during the data period (Table 14).

The inter-monsoon period in October (Period III in Figure 12) brought wind blowing mainly from the south and west most of the time. The prevailing wind speed during this period was between 0.3 and 3.3 m/s. The wind condition is similar to that of Period II. The maximum wind speed recorded was with the intensity between 8 and 10.7 m/s (Table 14). However, the percentage of the wind speed occurrence was small.

The Northeast Monsoon that occurs between November and March usually brings heavy rain to Sabah (Figure 8). From November to March, the prevailing wind recorded in most of the stations came from the north and east. Wind speed between 0.3 and 5.4 m/s dominated the period. The dominant wind speed interval gives light air and gentle breeze conditions (Table 13). Wind with an intensity of more than 10.7 m/s was also recorded during the Northeast Monsoon period (Table 14). However, the frequency of this wind speed was low.

Geographical Variability: Looking at the wind trend of each station from Period I to Period IV in Figure 12), it can be concluded that Labuan mainly experienced wind blowing from the south and west throughout the year, except during the Northeast Monsoon. The dominant wind speed ranged between 0.3 and 3.3 m/s. Kota Kinabalu, which is to the northeast of Labuan, was dominated by wind from the east most of the time. The prevailing wind speed was similar to that of Labuan. Kudat, which is at the northern tip of Sabah, experienced prevailing wind from the north and east direction during January and between November-March. On the other hand, wind from the south and west dominated the period between May and September, and October. The prevailing wind speed recorded at the Kudat station ranged between 0.3 and 5.4 m/s.

Sandakan, which is situated at the eastern fringe of Sabah, particularly experienced wind blowing from the northeast and southwest. The southwest wind was more prevalent between May and September, and also October. The northeast wind was experienced between November and March. The dominant wind speed ranged between 0.3 and 5.4 m/s. Tawau, which is located at the southern part of Sabah, experienced wind mainly from the north throughout the year. The prevailing wind speed recorded during the period of data ranged from 0.3 to 3.3 m/s.

Annual Variability: The trend of annual variability could not be analysed because annual data of wind speed and direction were not available at the time of writing.

Table 13: The Beaufort Scale and Wind Speed Intervals in Sabah

BEAUFORT SCALE   SABAH WIND SPEED INTERVALS
Sea ConditionsLand ConditionsForceSpeed (knots)m/s
Calm, sea like a mirror.Calm: Still: Smoke will rise vertically.0<1< 0.3
Light air, ripples only.Light Air: Rising smoke drifts, weather vane is inactive.11-30.3 – 1.5
Light breeze, small wavelets (0.2m). Crests have a glassy appearance.Light Breeze: Leaves rustle, can feel wind on your face, weather vane is inactive.24-61.6 – 3.3
Gentle breeze, large wavelets (0.6m), crests begin to break.Gentle Breeze: Leaves and twigs move around. Light weight flags extend.37-103.4 – 5.4
Moderate breeze, small waves (1m), some white horses.Moderate Breeze: Moves thin branches, raises dust and paper.411-165.5 – 7.9
Fresh breeze, moderate waves (1.8m), many white horses.Fresh Breeze: Moves trees sway.517-218.0 – 10.7
Strong breeze, large waves (3m), probably some spray.Strong Breeze: Large tree branches move, open wires (such as telegraph wires) begin to "whistle", umbrellas are difficult to keep under control.622-27> 10.7
Near gale, mounting sea (4m) with foam blown in streaks downwind.Moderate Gale: Large trees begin to sway, noticeably difficult to walk.728-33 

Gale, moderately high waves (5.5m), crests break into spindrift.

Fresh Gale: Twigs and small branches are broken from trees, walking into the wind is very difficult.834-40 
Strong gale, high waves (7m), dense foam, visibility affected.Strong Gale: Slight damage occurs to buildings, shingles are blown off of roofs.941-47 
Storm, very high waves (9m), heavy sea roll, visibility impaired. Surface generally white.Whole Gale: Large trees are uprooted, building damage is considerable.1048-55 
Violent storm, exceptionally high waves (11m), visibility poor.Storm: Extensive widespread damage. These typically occur only at sea, and rarely inland.1156-63 
Hurricane, 14m waves, air filled with foam and spray, visibility bad.Hurricane: Extreme destruction.1264+ 

Source: The Beaufort Scale: www.marinedata.co.uk; Wind Speed Intervals: Meteorological Department, Sabah

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32El Niņo is a disruption of the ocean-atmosphere system in the tropical Pacific having important consequences forweather around the globe. Among these consequences are increased rainfall across the southern tier of the US and in Peru, and drought in the west Pacific (including Malaysia). Source: U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration (http://www.noaa.gov/).

33La Niņa is characterised by unusually cold ocean temperatures in the equatorial Pacific, as compared to El Niņo, which is characterised by unusually warm ocean temperatures in the Equatorial Pacific. Source: U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration (http://www.noaa.gov/).

34Standard deviation is a measure of how widely dispersed values are from the average value.

35The duration and intervals of data for each station are not the same – Labuan (1979 – 1995), Kota Kinabalu (1968 – 1995), Kudat (1982 – 1995), Sandakan (1968 – 1995) and Tawau (1980 – 1995).