Title: Climate Time Series Seasonal Variability

Seasonal variability in climate time series is illustrated in Figures 1 though 3.

3 year Precip Time Series with orange boxes for falls and red for springs
Figure 1. Seasonal Variability of Precipitation Series at Roosevelt lake, Arizona. Boxes indicate 90 day time span in the horizontal and range of precipitation amount during the 90 days in the vertical.

Three years (1971 -1973) of daily precipitation time series are shown in Figure 1. Boxes illustrate variability for spring and fall seasons within these three years. Comparing box heights indicates general greater range (variability) of precipitation amount during falls than during springs. Also there is a suggestion that spring precipitation is generally less than in fall.

3 year Tmin Series with indication of warm and cold periods
Figure 2. Seasonal Variability of Daily Minimum Temperature for three years (1971-1973) at Central Park, New York

Figure 2 shows three annual cycles of cold and warm seasons. Even visually it could be seen that the range of temperature fluctuations during cold seasons is greater than it is during warm seasons, i.e. intraseasonal variability of cold seasons is greater than that of warm seasons.

30 year JFM averages time series with tend added
Figure 3. Temporal Variability of Seasonal Averages (DJF) of Minimum Daily Temperatures at Central Park, New York With a Linear Trend Added.

To analyze temporal variability of seasonal averages, all days within a cold season (example for DJF is shown in Figure 3) are averaged and plotted versus time. This plot illustrates interannual variability of the average temperature for the winter season.