def check_smonth(sdate, st_dict):
    """
    Function that checks if STILT model output is available for >= start date
    the check is for year and month only. 
    Example sdate = '2017-03-15' will return all stations which have data 
    for March 2017 or newer.
    """
    
    # if data exists in a year after sdate.year....True
    years = [int(y) for y in st_dict['years']]
    if any(y > sdate.year for y in years):
        return True 
    
    # if sdate.year is in years..check sdate.month 
    if sdate.year in years:
        months = [int(m) for m in st_dict[str(sdate.year)]['months']]
        if any(m >= sdate.month for m in months):
            return True
    return False