There is a cold summer this year in Sopot

Temp in Sopot/July 2015

The following CSV (on-demand generated from raw data with simple Perl script) file contains outdoor temperature registred every hour starting from 2010 (with DS18B20 sensor):

dayhr;No;y2010;y2011;y2012;y2013;y2014;y2015;day30
d070100;001;14.6;17.5;14.9;10.1;12.9;12.2;0
d070101;002;13.4;16.7;14.1;10.1;12.8;12.5;3600
d070102;003;12.8;16.3;14.3;10.2;12.7;12.1;7200

dayhr is a label and day30 denotes number of seconds from the beginning od the period (for the first observation day30 equals 0, for the second 3600 etc.) The chart was produced with the following custom R script:

require(ggplot2)
library(scales)
number_ticks <- function(n) {function(limits) pretty(limits, n)}

d <- read.csv("july-by-day.csv", sep = ';',  header=T, na.string="NA");

datestart <- ISOdate(2015, 7, 1, tz = "");
d30 <- datestart + d$day30;
d[,"d30"]  <- d30;

ggplot(d, aes(x = d30)) +
  geom_line(aes(y = y2015, colour = 'y2015'), size=.3) +
  geom_line(aes(y = y2014, colour = 'y2014'), size=.3) +
  geom_smooth(aes(y = y2015, colour = 'y2015'), size=1) +
  geom_smooth(aes(y = y2014, colour = "y2014"), size=1) +
  ylab(label="Temp [C]") +
  xlab(label="Observation") +
  scale_y_continuous(breaks=number_ticks(15)) +
  scale_x_datetime(breaks = date_breaks("5 days")) +
  theme(legend.title=element_blank()) +
  ggtitle("Temperature in July in Sopot") +
  theme(legend.position=c(.6, .9)) +
  theme(legend.text=element_text(size=12));

ggsave(file="Temp-M7-2015.pdf", width=15, height=8)