wx-temperature-plot

A small wxPython application that plots monthly temperature climatology (minimum and maximum averages, with optional 1-sigma error bars) for any city, fetched from the Open-Meteo historical weather archive.

The project is a working refactor of sample_two.py from the wxPython wiki page How to use Plot - Part 2 (Phoenix), extended with a separate fetch script that downloads real climate data from Open-Meteo.

Rome	Singapore	Reykjavik

Three climates side by side: the Mediterranean curve of Rome, the near-flat equatorial line of Singapore, and the narrow oceanic range of Reykjavik — all produced by the same script from Open-Meteo data.

Requirements

• Linux with GTK3 (tested on Debian 12)
• Python 3.x
• wxPython 4.x

On Debian / Ubuntu:

sudo apt install python3-wxgtk4.0

No pip dependencies. urllib, json, datetime are all in the standard library.

Usage

Two scripts, separation of concerns. fetch_temperatures.py downloads and aggregates raw daily data into temperatures.json. plot_temperatures.py reads the JSON and plots it.

# Show the bundled Rome sample.
python3 plot_temperatures.py

# Fetch fresh climatology for the default city (Rome, last 10 years).
python3 fetch_temperatures.py

# Or specify a city and time window.
python3 fetch_temperatures.py Reykjavik 5
python3 fetch_temperatures.py "Buenos Aires" 15

# Re-launch the GUI to view the new data.
python3 plot_temperatures.py

The GUI works offline once temperatures.json exists. Re-run the fetch whenever you want fresh data or a different location.

Files

fetch_temperatures.py    Network fetch and monthly aggregation.
plot_temperatures.py                 wxPython GUI that plots the JSON file.
temperatures.json        Plot data (Rome sample bundled).
icons/wxwin.ico          Optional window icon (silently skipped if absent).

Data source

Historical weather data from the Open-Meteo Historical Weather API, geocoding from the Open-Meteo geocoding endpoint, both licensed CC BY 4.0 and free for non-commercial use up to 10,000 daily calls. No API key required.

How standard deviation is computed

When fetch_temperatures.py produces the JSON, each monthly value is the arithmetic mean of all daily minima / maxima across the requested year range (about 300 daily observations per month for 10 years). The accompanying stddev is the sample standard deviation with Bessel's correction (n - 1 divisor), representing inter-annual variability of the typical day in that month. The plot draws each stddev as a vertical 1-sigma error bar.

History and credits

Once upon a time, in the wxpython-users mailing list...

In 2008 Mike Rooney posted a small example showing how to bend wx.lib.plot into accepting custom axis labels — an extension of Mike Driscoll's wxPython pyplot tutorial.

On 14 August 2014, building on that seed, Giuseppe ("beppe") Costanzi posted sample_app.py to the same group, in a thread titled wx.lib.plot: override ticks methods to customize labels. The demo plotted average Rome temperatures and showed how to override _xticks / _yticks to draw month abbreviations on the X axis and a °C suffix on the Y axis — the same override pattern still used in plot_temperatures.py today. Werner replied with Unicode and shebang fixes; Nathan McCorkle swapped the entry point from the old pysimpleapp helper to a plain wx.App subclass. Everything ran on Debian 6, Python 2.6, wxPython 2.8.

On 21 October 2020 Ecco ported the demo to wxPython Phoenix (wx 4.x), renamed it sample_two.py, and added it to the official wxPython wiki page How to use Plot - Part 2 (Phoenix), where it has lived ever since.

In May 2026 the original author returned to his own twelve-year-old code: snake_case throughout, the hardcoded Rome series moved out into a JSON file, automatic axis bounds, optional 1-sigma error bars, and a companion fetch script that pulls real climatology from the Open-Meteo historical weather archive for any city in the world.

Date	Author	File	Change
2008	Mike Rooney	—	Original wx.lib.plot custom-label example, extending Mike Driscoll's pyplot tutorial.
2014-08-14	Giuseppe Costanzi	sample_app.py	Posted to wxpython-users with the _xticks / _yticks override pattern still in use here.
2020-10-21	Ecco	sample_two.py	Ported to wxPython Phoenix, added to the official wxPython wiki.
2026-05	Giuseppe Costanzi	plot_temperatures.py, fetch_temperatures.py	Refactor: snake_case, externalised data, Open-Meteo integration, automatic axis bounds, 1-sigma error bars.

License

MIT. See LICENSE. Original 2010 attribution is preserved in the script headers and in the credits above.