How to compare datetime.now() with sunrise/sunset times from Sunrise-Sunset API in Python?

Question

I'm working on a Python script that checks whether it's currently dark outside based on my location (Barishal, Bangladesh). I use the Sunrise-Sunset API to get sunrise and sunset times, and then compare those to datetime.now().

import requests
from datetime import datetime

# My location
MY_LAT = 22.712647
MY_LNG = 90.351848

parameters = {
    "lat": MY_LAT,
    "lng": MY_LNG,
    "formatted": 0  # To get ISO 8601 format for easy datetime comparison
}

response = requests.get("https://api.sunrise-sunset.org/json", params=parameters)
data = response.json()

sunrise_utc = data["results"]["sunrise"]
sunset_utc = data["results"]["sunset"]

# Convert strings to datetime objects
sunrise_time = datetime.fromisoformat(sunrise_utc)
sunset_time = datetime.fromisoformat(sunset_utc)

# Current time
now = datetime.utcnow()

# Compare
if now < sunrise_time or now > sunset_time:
    print("It's dark outside")
else:
    print("It's daytime")

Even though it's nighttime here, my old script was returning "It's daytime" because the sunrise/sunset times were in UTC and not adjusted to my local time.

Answer 1

Documentation for sunrise-sunset.org suggests that you can use
tzid (string): A timezone identifier

parameters = {
    "lat": MY_LAT,
    "lng": MY_LNG,
    "formatted": 0,  # To get ISO 8601 format for easy datetime comparison
    "tzid": "Asia/Dhaka",
}

And this gives me values with UTC+06:00 instead of UTC

And to get current time with the same timezone I needed

from zoneinfo import ZoneInfo

zone_info = ZoneInfo("Asia/Dhaka")

now = datetime.now(zone_info)

or

time_zone = datetime.timezone(datetime.timedelta(hours=6)) #, "UTC+06:00")

now = datetime.datetime.now(time_zone)

Without this I get error when it compares now < sunrise_time because datetime.utcnow() gives me time without timezone and it doesn't know how to compare times.

---

Command datetime.datetime.utcnow() gives warning that it is deprecated and it should be used datetime.datetime.now(datetime.UTC)

---

Full working code with extra info:

import requests
import datetime
from zoneinfo import ZoneInfo

# My location
MY_LAT = 22.712647
MY_LNG = 90.351848

zone_name = "Europe/Warsaw"
zone_name = "Asia/Dhaka"
#zone_name = "UTC+06:00"  # doesn't work in API and ZoneInfo

parameters = {
    "lat": MY_LAT,
    "lng": MY_LNG,
    "formatted": 0,  # To get ISO 8601 format for easy datetime comparison
    "tzid": zone_name,
}

response = requests.get("https://api.sunrise-sunset.org/json", params=parameters)
data = response.json()
#print(data)

sunrise_utc = data["results"]["sunrise"]
sunset_utc = data["results"]["sunset"]

# Convert strings to datetime objects
sunrise_time = datetime.datetime.fromisoformat(sunrise_utc)
sunset_time = datetime.datetime.fromisoformat(sunset_utc)

# Current time
now = datetime.datetime.utcnow().replace(microsecond=0)
print('\n--- utcnow() ---')
print(f"{now = }")
print(f"{now.tzinfo = }")
print(now)

now = datetime.datetime.now(datetime.UTC).replace(microsecond=0)
print('\n--- now(datetime.UTC) ---')
print(f"{now = }")
print(f"{now.tzinfo = }")
print(now)

zone_info = ZoneInfo(zone_name)
now = datetime.datetime.now(zone_info).replace(microsecond=0)
print('\n--- now(ZoneInfo) ---')
print(f"{now = }")
print(f"{now.tzinfo = }")
print(now)

zone_info = datetime.timezone(datetime.timedelta(hours=6)) #, "UTC+06:00")
now = datetime.datetime.now(zone_info).replace(microsecond=0)
print('\n--- now(timezone) ---')
print(f"{now = }")
print(f"{now.tzinfo = }")
print(now)

print('\n------')
print(f'now: {now} | {now.tzinfo}')
print(f'sr : {sunrise_time} | {sunrise_time.tzinfo}')
print(f'ss : {sunset_time} | {sunset_time.tzinfo}')

# Compare
if now < sunrise_time or now > sunset_time:
    print("It's dark outside")
else:
    print("It's daytime")

Result:

./main.py:38: DeprecationWarning: datetime.datetime.utcnow() is deprecated and scheduled for removal in a future version. Use timezone-aware objects to represent datetimes in UTC: datetime.datetime.now(datetime.UTC).
  now = datetime.datetime.utcnow().replace(microsecond=0)

--- utcnow() ---
now = datetime.datetime(2025, 8, 8, 7, 38, 5)
now.tzinfo = None
2025-08-08 07:38:05

--- now(datetime.UTC) ---
now = datetime.datetime(2025, 8, 8, 7, 38, 5, tzinfo=datetime.timezone.utc)
now.tzinfo = datetime.timezone.utc
2025-08-08 07:38:05+00:00

--- now(ZoneInfo) ---
now = datetime.datetime(2025, 8, 8, 13, 38, 5, tzinfo=zoneinfo.ZoneInfo(key='Asia/Dhaka'))
now.tzinfo = zoneinfo.ZoneInfo(key='Asia/Dhaka')
2025-08-08 13:38:05+06:00

--- now(timezone) ---
now = datetime.datetime(2025, 8, 8, 13, 38, 5, tzinfo=datetime.timezone(datetime.timedelta(seconds=21600), 'UTC+06:00'))
now.tzinfo = datetime.timezone(datetime.timedelta(seconds=21600), 'UTC+06:00')
2025-08-08 13:38:05+06:00

------
now: 2025-08-08 13:38:05+06:00 | UTC+06:00
sr : 2025-08-08 05:31:36+06:00 | UTC+06:00
ss : 2025-08-08 18:36:54+06:00 | UTC+06:00
It's daytime

---

By The Way:

There is also Python module Astral which can calculate it without using Internet.

Difference is ~1.5 minutes.

You create location (if it doesn't have it in "database") and it can calculate sun position for your timezone.

import datetime
from astral import LocationInfo
from astral.sun import sun

MY_LAT = 22.712647
MY_LNG = 90.351848

city = LocationInfo(latitude=MY_LAT, longitude=MY_LNG)

time_zone = datetime.timezone(datetime.timedelta(hours=6))  # "UTC+06:00"

info = sun(city.observer, tzinfo=time_zone)

print('sunrise:', info['sunrise'])
print('sunset :', info['sunset'])
print('length :', info['sunset'] - info['sunrise'])

Longer version which calculates also for tomorrow and yesterday

import datetime
#import astral
from astral import LocationInfo
from astral.sun import sun
from astral.geocoder import database, lookup

# My location
MY_LAT = 22.712647
MY_LNG = 90.351848

#city = LocationInfo("Barishal", "Asia", "Asia/Barishal", 22.712647, 90.351848)
#city = LocationInfo(name="Barishal", region="Asia", timezone="Asia/Barishal", latitude=MY_LAT, longitude=MY_LNG)
#city = LocationInfo(latitude=MY_LAT, longitude=MY_LNG)
db = database()
#city = db['asia']['dhaka'][0]  # lowercase
city = lookup('Dhaka', db)     
print(city)

time_zone = datetime.timezone(datetime.timedelta(hours=6)) 

one_day = datetime.timedelta(days=1)
today = datetime.date.today() 

print('--- today ---')

info = sun(city.observer, tzinfo=time_zone)
#info = sun(city.observer, date=today, tzinfo=time_zone)

print('sunrise:', info['sunrise'].replace(microsecond=0))
print('sunset :', info['sunset'].replace(microsecond=0))
print('length :', info['sunset'] - info['sunrise'])

print('--- tomorrow ---')

tomorrow = today + one_day
info = sun(city.observer, date=tomorrow, tzinfo=time_zone)

print('sunrise:', info['sunrise'].replace(microsecond=0))
print('sunset :', info['sunset'].replace(microsecond=0))
print('length :', info['sunset'] - info['sunrise'])

print('--- yesterday ---')

yesterday = today - one_day
info = sun(city.observer, date=yesterday, tzinfo=time_zone)

print('sunrise:', info['sunrise'].replace(microsecond=0))
print('sunset :', info['sunset'].replace(microsecond=0))
print('length :', info['sunset'] - info['sunrise'])

Result:

--- today ---
sunrise: 2025-08-08 05:32:53+06:00
sunset : 2025-08-08 18:35:20+06:00
length : 13:02:26.340931
--- tomorrow ---
sunrise: 2025-08-09 05:33:17+06:00
sunset : 2025-08-09 18:34:39+06:00
length : 13:01:22.427021
--- yesterday ---
sunrise: 2025-08-07 05:32:30+06:00
sunset : 2025-08-07 18:35:59+06:00
length : 13:03:29.519594