Date and time

The first step in setting up the environment is to specify the date and time of the flight that will be simulated.

Basic usage

RocketPy requires detailed date and time information, including the year, month, day, and hour, to accurately forecast the weather. Additionally, a timezone can be specified to localize the time.

from rocketpy import Environment

env = Environment(
    date=(2022, 2, 16, 18), # year, month, day, hour
    timezone="America/New_York"
)

Tip

To view a list of available timezones, use the following code:

import pytz

print(pytz.all_timezones)

Tip

When the timezone is omitted, RocketPy assumes it is given in standard UTC.

See also

For more information on timezones, see pytz.

Using datetime objects

The date argument also supports datetime objects, which are python built-in objects that represent a date and time.

from datetime import datetime
from rocketpy import Environment

date = datetime(2022, 2, 16, 18)
env = Environment(date=date)

Setting tomorrow’s date

In the examples we will cover next, it is quite common to set the launch date to tomorrow. This can be done by using the datetime module to calculate the date of tomorrow.

from datetime import date, timedelta

tomorrow = date.today() + timedelta(days=1)

date_info = (tomorrow.year, tomorrow.month, tomorrow.day, 9)  # Hour given in UTC time

print("Tomorrow's date:", date_info)

Tomorrow's date: (2026, 4, 7, 9)

Note

The code above will set the date to tomorrow at 9:00 UTC time. The hour can be adjusted as needed.

Danger

The datetime module in Python contains both the date and timedelta classes, as well as the datetime class. The datetime class is used to create datetime objects. It is common to confuse the datetime module (which includes various classes and methods for manipulating dates and times) with the datetime class itself (which is used to create specific datetime objects). See the official documentation for more information.

Alternatively, you can use the datetime module to calculate the date of tomorrow at the same time as the current time, and then pass it to the Environment class.

from datetime import datetime, timedelta
from rocketpy import Environment

tomorrow = datetime.now() + timedelta(days=1)

env = Environment(date=tomorrow)

Note

The code above will set the environment to tomorrow’s date at the same time as the current time.