what was the best record in a month for the any team since 1900 (minimum 20 games)

Since 1900, the Detroit Tigers have the best record by a team with 20+ games played in a month, with a record of 18-2 in April 1984.

	TEAM	REC	G	MONTH	W%	W	L	AB	R	H	2B	3B	HR	RBI	BB	HBP	SO	SB	CS	PA	TB	XBH	SH	SF	IBB	GIDP	AVG	OBP	SLG	OPS
1	Tigers	18-2	20	April 1984	.900	18	2	716	120	206	39	6	22	113	83	4	111	18	13	811	323	67	7	1	7	20	.288	.364	.451	.816
2	Cubs	26-3	29	August 1906	.897	26	3	883	140	244	29	10	2		92	8		38		1,039	299	41	56				.276	.350	.339	.689
3	Giants	24-3	27	August 1936	.889	24	3	976	141	287	31	6	21	133	69	5	73	9		1,074	393	58	24				.294	.344	.403	.746
4	Cubs	23-3	26	September 1935	.885	23	3	902	156	271	46	11	10	138	77	8	74	12		1,017	369	67	30				.300	.361	.409	.770
5	Dodgers	20-3	23	July 2017	.870	20	3	767	107	211	44	7	35	105	88	6	199	7	5	869	374	86	4	4	10	17	.275	.353	.488	.840
6	Pirates	19-3	22	June 1909	.864	19	3	757	110	228	27	16	2		74	5		36		866	293	45	30				.301	.367	.387	.754
7	Indians	25-4	29	September 2017	.862	25	4	1,001	164	283	68	7	44	158	103	15	180	12	3	1,132	497	119	0	13	7	22	.283	.354	.497	.851
8	Yankees	25-4	29	July 1941	.862	25	4	1,036	172	301	56	10	35	163	125	7	97	12		1,179	482	101	11			18	.291	.371	.465	.836
9	Athletics	24-4	28	August 2002	.857	24	4	998	164	278	55	10	40	161	93	14	148	7	5	1,112	473	105	2	5	12	19	.279	.347	.474	.821
10	Brewers	18-3	21	April 1987	.857	18	3	738	135	218	40	5	29	130	81	6	136	26	7	843	355	74	12	6	10	15	.295	.367	.481	.848
11	Athletics	18-3	21	April 1981	.857	18	3	701	105	175	26	5	22	100	79	4	122	27	9	800	277	53	13	3	4	7	.250	.328	.395	.723
12	Giants	24-4	28	June 1954	.857	24	4	969	139	261	41	4	30	136	98	8	112	9	7	1,100	400	75	15	10		17	.269	.338	.413	.751
13	Yankees	24-4	28	May 1939	.857	24	4	978	213	284	49	12	32	200	156	12	91	25		1,164	453	93	18			11	.290	.394	.463	.858
14	Giants	29-5	36	September 1916	.853	29	5	1,130	154	302	41	17	13	126	80	7	127	54		1,247	416	71	30				.267	.320	.368	.688
15	Cardinals	23-4	28	August 1944	.852	23	4	954	163	283	57	14	20	154	134	8	86	5		1,126	428	91	30			18	.297	.388	.449	.836
16	Athletics	23-4	27	May 1931	.852	23	4	989	177	298	63	12	32	170	96	6	78	3		1,105	481	107	14				.301	.367	.486	.853
17	Dodgers	17-3	20	April 1977	.850	17	3	707	132	216	46	4	29	127	91	4	111	19	10	823	357	79	12	9	20	9	.306	.383	.505	.888
18	Pirates	17-3	20	June 1903	.850	17	3	695	121	211	29	12	6	111	51	7	30	21		767	282	47	14				.304	.357	.406	.763
19	Giants	22-4	26	June 1912	.846	22	4	884	217	299	59	21	13	186	99	12	84	68		1,028	439	93	33				.338	.412	.497	.909
20	Pirates	22-4	26	May 1902	.846	22	4	885	166	268	32	25	4	138	94	9	79	37		1,014	362	61	26				.303	.376	.409	.785
21	Braves	21-4	25	June 2023	.840	21	4	880	175	269	41	4	61	168	92	5	176	27	4	987	501	106	0	10	3	22	.306	.371	.569	.940
22	Cardinals	21-4	25	September 1942	.840	21	4	866	113	228	45	12	7	102	72	1	76	13		969	318	64	30			13	.263	.321	.367	.688
23	Cardinals	21-4	25	September 1930	.840	21	4	901	183	298	69	18	16	176	65	5	89	12		999	451	103	28				.331	.379	.501	.880
24	White Sox	21-4	26	August 1906	.840	21	4	788	117	183	27	13	2		75	11		36		921	242	42	47				.232	.308	.307	.615
25	Braves	26-5	34	September 1914	.839	26	5	1,112	183	309	64	13	5		121	13	133	26		1,304	414	82	58				.278	.356	.372	.728