Matplotlib: Dates

Date axis ticks label format

import matplotlib.dates as mdates

formatter = mdates.DateFormatter('%Y-%m-%d %H:%M:%S')
ax.xaxis.set_major_formatter(formatter)

Set date autoformatter:

plt.rcParams['date.autoformatter.day'] = '%b %d\n%H:%M'
plt.rcParams['date.autoformatter.hour'] = '%b %d\n%H:%M'

Date axis tick location

import matplotlib.dates as mdates
ax.xaxis.set_major_locator(mdates.HourLocator(range(0, 24, 3)))
ax.xaxis.set_minor_locator(mdates.HourLocator(range(0, 24, 1)))

Tick format and location

import pandas as pd
from matplotlib.dates import HourLocator, DateFormatter

x = pd.date_range("2017-01-01", "2017-01-02", freq="h")
y = range(len(x))
plt.plot(x, y, marker=".")
plt.gca().xaxis.set_major_locator(HourLocator(byhour=range(0, 24, 6)))
plt.gca().xaxis.set_minor_locator(HourLocator(byhour=range(0, 24, 1)))
plt.gca().xaxis.set_major_formatter(DateFormatter("%d %b %Y\n%H:%M\n%A"))

Custom tick format

Say I want to have ticks on the zeroth hour of the day have an expanded label…

import pandas as pd
import matplotlib.ticker as mticker

def custom_date_formatter(x, pos):
    """Custom date format by hour."""
    date = mdates.num2date(x)  # Convert from Matplotlib's float date to datetime
    if date.hour == 0:
        return date.strftime("%H:%M\n%d %b\n%Y")
    else:
        return date.strftime("%H:%M")


x = pd.date_range("2017-01-01", "2017-01-02 6:00", freq="h")
y = range(len(x))
plt.plot(x, y, marker=".")

ax = plt.gca()
ax.xaxis.set_major_formatter(mticker.FuncFormatter(custom_date_formatter))

Dates and colorbars

Use Dates on Colorbar Ticks https://github.com/matplotlib/matplotlib/issues/17447#issuecomment-630885219