In the event you only trim your fingernails "every morning that the date is a prime number and the day of the week is named after a Norse deity," then this is a simple script to help you decide whether you should trim them or not.

toTrimOrNotToTrimToday.py

import datetime

# Check whether number is prime
# Source: http://www.cs.armstrong.edu/liang/py/html/PrimeNumberFunction.html
def isPrime(number):
    divisor = 2
    while divisor <= number / 2:
        if number % divisor == 0:
            # If true, number is not prime
            return False # number is not a prime
        divisor += 1

    return True # number is prime

# Days of the week that are named after a Norse deity:
# Tuesday, Thursday, and Friday.
# Source: http://en.wikipedia.org/wiki/Names_of_the_days_of_the_week#Germanic_tradition
# 0 being Monday...
daysOfTheWeek = [1, 3, 4]

# Check (and print) whether or not we should trim our nails today.
# This is based on if the day is named after a Norse deity,
# or the date (day of the month) is a prime number.
def checkNailTrimmingForDate(day):
    dayIsPrime = isPrime(day.day)
    dayIsNorseBased = (day.weekday() in daysOfTheWeek)

    # Print the date leading our conclusion.
    print(day.strftime('%A') + ', the ' + str(day.day)),

    # Print the four possible results.
    if dayIsPrime:
        if dayIsNorseBased:
            print('is the day! You better be trimming on it.')
        else:
            print('is a prime, but not named after a Norse deity. No nail trimming for you.')
    else:
        if dayIsNorseBased:
            print('is named after a Norse deity, but it isn\'t a prime number. Restrain thy trimming, lest ye be struck down.')
        else:
            print('is not a prime number, nor is it named after a Norse deity...No need to trim your fingernails.')

# Check if we should trim our nails today.
today = datetime.datetime.today()
checkNailTrimmingForDate(today)

Mr. Burgess, you're a hero.