The following chart plots the average performance of the FTSE 100 Index during April since 1984 (more info on this type of chart).
The chart shows that on average the market steadily climbs throughout the whole month ending at the month’s high.
The average chart for March was posted a month ago here. The following reproduces that chart and overlays the actual FTSE 100 for March 2013.
On average the UK market climbs for the first three weeks of March and then falls back towards the end of the month; this year the market broadly followed the overall pattern, except shifted forward by a week: the market peaked at the end of the second week and then tailed off to the month end.