[R] Help with plotting and date-times for climate data

[Richard O'Keefe]

Off-topic, but what is a "mean temperature max"
and what good would it do you to know you if you did?
I've been looking at a lot of weather station data
and for no question I've ever had (except "would the
newspapers get excited about this") was "max" (or min)
the answer.  Considering the way that temperature can
change by several degrees in a few minutes, or a few
metres -- I meant horizontally when I wrote that, but
as you know your head and feet don't experience the
same temperature, again by more than one degree -- I am
at something of a loss to ascribe much practical
significance to TMAX.  Are you sure this is the analysis
you want to do?  Is this the most informative data you
can get?

On Wed, 13 Sept 2023 at 08:51, Kevin Zembower via R-help <
r-help using r-project.org> wrote:

> Hello,
>
> I'm trying to calculate the mean temperature max from a file of climate
> date, and plot it over a range of days in the year. I've downloaded the
> data, and cleaned it up the way I think it should be. However, when I
> plot it, the geom_smooth line doesn't show up. I think that's because
> my x axis is characters or factors. Here's what I have so far:
> ========================================
> library(tidyverse)
>
> data <- read_csv("Ely_MN_Weather.csv")
>
> start_day = yday(as_date("2023-09-22"))
> end_day = yday(as_date("2023-10-15"))
>
> d <- as_tibble(data) %>%
>     select(DATE,TMAX,TMIN) %>%
>     mutate(DATE = as_date(DATE),
>            yday = yday(DATE),
>            md = sprintf("%02d-%02d", month(DATE), mday(DATE))
>            ) %>%
>     filter(yday >= start_day & yday <= end_day) %>%
>     mutate(md = as.factor(md))
>
> d_sum <- d %>%
>     group_by(md) %>%
>     summarize(tmax_mean = mean(TMAX, na.rm=TRUE))
>
> ## Here's the filtered data:
> dput(d_sum)
>
> > structure(list(md = structure(1:25, levels = c("09-21", "09-22",
> "09-23", "09-24", "09-25", "09-26", "09-27", "09-28", "09-29",
> "09-30", "10-01", "10-02", "10-03", "10-04", "10-05", "10-06",
> "10-07", "10-08", "10-09", "10-10", "10-11", "10-12", "10-13",
> "10-14", "10-15"), class = "factor"), tmax_mean = c(65,
> 62.2222222222222,
> 61.3, 63.8888888888889, 64.3, 60.1111111111111, 62.3, 60.5, 61.9,
> 61.2, 63.6666666666667, 59.5, 59.5555555555556, 61.5555555555556,
> 59.4444444444444, 58.7777777777778, 55.8888888888889, 58.125,
> 58, 55.6666666666667, 57, 55.4444444444444, 49.7777777777778,
> 48.75, 43.6666666666667)), class = c("tbl_df", "tbl", "data.frame"
> ), row.names = c(NA, -25L))
> >
> ggplot(data = d_sum, aes(x = md)) +
>     geom_point(aes(y = tmax_mean, color = "blue")) +
>     geom_smooth(aes(y = tmax_mean, color = "blue"))
> =====================================
> My questions are:
> 1. Why isn't my geom_smooth plotting? How can I fix it?
> 2. I don't think I'm handling the month and day combination correctly.
> Is there a way to encode month and day (but not year) as a date?
> 3. (Minor point) Why does my graph of tmax_mean come out red when I
> specify "blue"?
>
> Thanks for any advice or guidance you can offer. I really appreciate
> the expertise of this group.
>
> -Kevin
>
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