Newly - daily data from Prague Klementinum are aviable at portal.chmi.cz too for period 1775-2017, pretty long period. There was heat island always, but surrounding of station have been changed. This data set is not the same like ECAD data sets some values are in difference. Precipitation are aviable since may 1804.
In period 1775-1830 cca - temperature amplitude during day was smaller, minimum temperature higher and maximum temperature lower. It affected statistics of occurrence some days. It can be because of volcanic ash.
Month with highest average temperature is still august 1807 (whole month Tmin 17.0), coldest month with coldest anomaly and coldest Tmax 0.0 is February 1929. Maximum number of days with Tmax bellow zero per month is 30. Lowest temperature anomaly, lowest maximum, average daily temperature is from 22.1.1850, lowest minimum temperature is from 1.3.1785 (and last day with Tma bellow -10 is 28.2.1785). Highest minimum temperature is from August 2015 and highest maximum temperature still from 27.7.1983.
Last year without Tmax 30 was in 1916, there are two years with Tmax bellow 27 (+26.4 i 1821 and +26.5 in 1786). 1956 was quite close - only one day with Tmax +30.0. Last year with Tmax bellow 30 in all Czech stations is 1864, it was much less stations in Czech. There was 7 year period without Tmax 30 1812-1818. Last Arctic day in Klementinum is 30.12.1996 (by ECAD 31.12.1996) and maximum number of Arctic days was 15 in year 1799.
GREEN - average annual values or sum of precipitation.
RED - maximum daily value during year.
BLUE - minimum daily value during year.
GREEN - number of days during year with some specification.
Trends are always linear. Derivation - number before X, is change by one year, constant value is not important.
For every day - during year - normal temperature Tmax, Tmin, Tavg was calculated from ECAD data 1775-2004 and anomaly of Tmax, Tmin, Tavg is from this data.