How to add time as a feature into clustering algorithm?
I've decided to try LDA:

cvectorizer = CountVectorizer(min_df=4, max_features=10000, ngram_range(1,2))
cvz = cvectorizer.fit_transform(df['word'])
n_topics = 32
n_iter = 2000
lda_model = lda.LDA(n_topics=n_topics, n_iter=n_iter)
X_topics = lda_model.fit_transform(cvz)


Then I've concatenated time feature to the LDA vector:

 X_all  = np.hstack((X_topics, X_time))


Where X_time was my time feature column.