def month_labels(months):
    
    """ Retrieve month labels for keying corr maps and plotting .
    
    Parameters
    ----------
    months : result of warm_months func

    Returns
    -------
    4-keyed dictionary with labels for 3 individual months and 'month1 - month2 - month3'
    """    
    
    month_dict = {1: 'January',
                  2: 'February',
                  3: 'March',
                  4: 'April',
                  5: 'May',
                  6: 'June',
                  7: 'July',
                  8: 'August',
                  9: 'September',
                  10: 'October',
                  11: 'November',
                  12: 'December'}
    labels = {}
    
    for month in months:
        
        labels[month] = month_dict[month]
        
    labels['all'] = month_dict[months[0]] + ' - ' +month_dict[months[1]] + ' - ' + month_dict[months[2]]
    return labels