Summary of Weather in the Cameron Highlands – 2nd Edition By: Erica Jenkins (ericasjenkins@gmail.com)

 

There is a weather station in the Cameron Highlands at 1545 meters above sea level.  This weather station has been collecting weather data since April 1983, including precipitation, temperature, wind speed, and evaporation.  The following report summarizes these data.

 

Precipitation – Monthly Precipitation

Data from the station at 1545 m indicates that the mean monthly rainfall is 338 mm per month, with an average of 20 rain days per month.  The greatest amount of precipitation occurs during October and November, with mean monthly rainfall of 368 mm and 329 mm, respectively (Figure 1).  Another peak in yearly precipitation occurs in April and May; the mean rainfall in April is 271 mm, while the mean in May is 272 mm.  The least amount of rain fell in January, with an average of 111 mm, and February, with an average of 135 mm of rain.  Generally, the number of rain days and the amount of precipitation are strongly related, which is not surprising.  This is evident in figure 1 as the peaks and troughs in the number of rain days are quite similar to those in the average amount of precipitation.

 Mean Monthly rainfall

Figure 1.  Mean rainfall and mean number of rain days per month.  Monthly averages based on the years 1984 to 2011 (some data for the year 2001 was unavailable).

 

 

Precipitation – Yearly Precipitation

 

The average amount of precipitation at 1545 m in the Cameron highlands was 2852 mm per year with an average of 236 rain days per year.  The greatest amount of precipitation fell in the years 1999 and 2008 with 3707 mm and 3952 mm, respectively (Figure 2).  The least amount of precipitation occurred in the years 1986 and 1990 with 2836 mm and 2282 mm, respectively.  The amount of precipitation and the number of rain days appeared to be related, though the greatest number of rain days occurred in 1984 with 272 rain days, and the least number of rain days occurred in 2002, with 203 days of rain.  The years with the greatest amount of rain appeared to coincide with La Niña years; La Niña events occurred 1999 and 2008, although the events were moderate (based on data from NOAA website: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ ensostuff/ensoyears.shtml).

Monitoring average

Figure 2. Yearly total rainfall (mm) and number of rain days at an elevation of 1545m in the Cameron Highlands for each year from 1984 to 2011 (data for the year 2001 is not included due to missing values).

 

Mean yearly precipitation

 

Temperature – Monthly Mean Temperatures

 

The mean temperature at 1545 m in the Cameron highlands for the years 1984 to 2011 was 17.9 ˚C, the mean minimum temperature was 15.3 ˚C, and the mean maximum temperature was 22.4 ˚C (Figure 3).  Temperatures tended to be highest in April and May, when the mean temperatures were 18.6 ˚C and 18.7 ˚C, respectively.

 

Mean temperature

Mean minimum temperature

Mean maximum temperature

Figure 3.  Mean temperature, mean minimum temperature, and mean maximum temperature for each month.  Means based on data collected for the years 1984 to 2011 (data for the year 2001 was unavailable).

 

Temperature – Yearly Mean Temperatures

 

The year 1998 was the warmest year recorded in the Cameron Highlands at 1545 m since 1984.  The mean temperature was 18.5 ˚C, the mean maximum temperature was 23.4 ˚C, and the mean minimum temperature was 15.9 ˚C.  There was a strong El Niño event that occurred during the later half of 1997 and the beginning of 1998, which may account for the anomalous temperatures.  At 17.7 ˚C, the mean temperature in the year 1984 was relatively low, although this does not appear to coincide with a La Niña event.  In the years from 1984 to 1998, there appears to be an increasing trend in the mean maximum temperature (as discussed in the previous edition of this paper), but the trend does not appear to continue into the new millennium (R2 = 0.28, p = 0.18).  The statistical analysis used to draw this conclusion, namely, the regression of the mean temperature versus the year, is not a particularly robust test, and significant results could occur with more in-depth statistical analysis.

 

 

 

Figure 4. Mean monthly temperature, minimum temperature and maximum temperature at an elevation of 1545m in the Cameron Highlands for each year from 1984 to 2011 (data for the year 2001 is not included due to missing values).  The trend-lines indicate the relationship between mean temperature and year, but no significant relationships were found.

 

Wind Speed and Evaporation – Monthly

 

The mean wind speed for the years 1984 to 2011 at 1545 m in the Cameron Highlands was 2.0 m/s.  The greatest mean wind speeds occurred in January and December, at 2.8 m/s and 2.6 m/s, respectively (Figure 5).  The lowest mean wind speeds occurred in May at 1.5 m/s.  The mean daily evaporation was greatest in February and March with an average of 2.3 mm per day in both of those months.  The lowest levels of evaporation occurred in November and December, with an average of 1.6 mm per day in both of those months.

 

Wind Speed and Evaporation – Yearly

 

The greatest mean wind speed occurred in the year 1990, with an average wind speed of 2.3 m/s.  The lowest mean wind speeds occurred in the years 1984 and 2004, with a mean wind speed in both years of 1.7 m/s (Figure 6).  The mean daily evaporation was greatest the year 2005 with an average of 2.5 mm per day.  The lowest levels of evaporation occurred in the years 1999, 2003, and 2011, with an average of 1.6 mm per day in each of those years.

 

 

 

 

Figure 5.  Mean wind speed and daily evaporation per month for the years 1984 to 2011 (data for the years 2000 and 2001 was unavailable).

 

 

Figure 6. Mean wind speed and mean daily evaporation at an elevation of 1545m in the Cameron Highlands for each year from 1984 to 2011 (data for the years 2000 2001 was unavailable).