Change date order at axis - r

Question

I am always struggeling with this, so I think it is finally time to ask some help...
I tried to make a reproducible example, but for some reason I cannot get my x$monthday in the %m-%d format :(.
x<-data.frame(seq(as.POSIXct('2012-10-01'), as.POSIXct('2015-03-01'), by= "day"))
names(x)<- "date"
x$month<- months(x$date)
x$monthday<- as.POSIXct(x$date, format= "%m-%d")
x1<- x[x$month== 'October' |x$month== 'November' | x$month== 'December' |x$month== 'January'|x$month== 'February', ]
y<- 1: nrow(x1)
x2<-cbind(x1, y)
x3<- aggregate(list(y=x2$y), list(monthday=x2$monthday), mean)
plot(x3$monthday, x3$y)
The date has the format of %m/%d and is of a time series from October-March.
R orders the axis beautifully from January to December, which causes a big gap in between, because my data range from October-March.
How can I make my x axis order in the form from October-March?
Thank you very much in advance.

Answer 1

library(dplyr)
library(ggplot2)
library(lubridate)
# Fake data
dat <- data.frame(date=seq(as.POSIXct('2012-10-01'), as.POSIXct('2015-03-01'), by="day"))
set.seed(23)
dat$temperature = cumsum(rnorm(nrow(dat)))
# Subset to October - March
dat <- dat[months(dat$date) %in% month.name[c(1:2,10:12)], ]
# Calculate mean daily temperature
dat = dat %>% group_by(Month=month(date), Day=day(date)) %>%
summarise(dailyMeanTemp = mean(temperature)) %>%
mutate(newDate = as.Date(ifelse(Month %in% 10:12,
paste0("2014-", Month, "-", Day),
paste0("2015-", Month, "-", Day))))
The mutate function above creates a fake year, only so that we can keep the dates in "date" format and get them ordered from October to March. There's probably a better way to do it (maybe a function in the zoo or xts packages), but this seems to work.
ggplot(dat, aes(newDate, dailyMeanTemp)) +
geom_line() + geom_point() +
labs(y="Mean Temperature", x="Month")
Or, in base graphics:
plot(dat$newDate, dat$dailyMeanTemp)