A method to get first tmp dir in list and set it to environ so tempfile.mkstemp can use anywhere and you too at any place since it cache on os.environ.

get_tmpdir.py

def get_tmpdir(tmpdirs=tuple()):

    # use a kind of cache
    if not tmpdirs and os.environ.get('SET_TMPDIR_CHOICE',False):
        return os.environ['SET_TMPDIR_CHOICE']

    # starting here is a snipped copyed from /usr/lib/python2.7/tempfile.py
    dirlist = []

    # First, try the environment.
    for envname in 'TMPDIR', 'TEMP', 'TMP':
        dirname = os.getenv(envname)
        if dirname: dirlist.append(dirname)

    # Failing that, try OS-specific locations.
    if os.name == 'riscos':
        dirname = _os.getenv('Wimp$ScrapDir')
        if dirname: dirlist.append(dirname)
    elif os.name == 'nt':
        dirlist.extend([ r'c:\temp', r'c:\tmp', r'\temp', r'\tmp' ])
    else:
        dirlist.extend([ '/tmp', '/var/tmp', '/usr/tmp' ])

    # As a last resort, the current directory.
    try:
        dirlist.append(os.getcwd())
    except (AttributeError, _os.error):
        dirlist.append(os.curdir)

    # ending here the snipped copyed from /usr/lib/python2.7/tempfile.py

    # set temp dir default list
    default_tmp_dirs = (
        os.path.join(os.environ.get('VIRTUAL_ENV'),sys.prefix), # venv/tmp, read http://www.python.org/dev/peps/pep-0405/
        os.path.join(settings.PROJECT_ROOT_PATH,'tmp'), # project/tmp, project root path is defined on settings.py
    ) + tuple(dirlist)

    for tmpdir in tmpdirs+default_tmp_dirs:

        if not os.path.exists(tmpdir):
            try:
                os.makedirs(tmpdir)
            except OSError:
                continue # failed on create dir, no permission or existent file

        if not os.path.isdir(tmpdir):
            continue # is file

        if not os.access(tmpdir,os.W_OK):
            continue # not writeable

        # set tmpdir environ variables
        os.environ['TMPDIR'] = tmpdir
        os.environ['TEMP'] = tmpdir
        os.environ['TMP'] = tmpdir
        # set a cache uniq var that we use as like cache key
        os.environ['SET_TMPDIR_CHOICE'] = tmpdir

        return tmpdir

    raise OSError,u"Any temporary directory can be used, specify one."