The St. Louis Browns had their lowest winning percentage in a season in 1939, winning 27.9 percent of the time.

	TEAM	W%	SEASON	W	L	G	AB	R	H	2B	3B	HR	RBI	BB	HBP	SO	SB	CS	PA	TB	XBH	SH	SF	IBB	GIDP	AVG	OBP	SLG	OPS
1	Browns	.279	1939	43	111	156	5,422	733	1,453	242	50	91	696	558	20	606	48	38	6,132	2,068	383	132			121	.268	.339	.381	.720
2	Orioles	.290	2018	47	115	162	5,507	622	1,317	242	15	188	593	422	57	1,412	81	22	6,034	2,153	445	13	35	19	132	.239	.298	.391	.689
3	Browns	.296	1911	45	107	152	4,996	566	1,192	187	63	17	473	460	34	785	125		5,632	1,556	267	142				.239	.307	.311	.619
4	Browns	.299	1937	46	108	156	5,510	715	1,573	327	44	71	682	514	14	510	30	27	6,123	2,201	442	85				.285	.348	.399	.747
5	Browns	.305	1910	47	107	158	5,077	454	1,105	131	60	12	347	415	36	841	169		5,671	1,392	203	143				.218	.281	.274	.556
6	Orioles	.321	2021	52	110	162	5,420	659	1,296	266	15	195	632	451	65	1,454	54	23	5,981	2,177	476	14	31	12	105	.239	.304	.402	.705
7	Orioles	.333	2019	54	108	162	5,596	729	1,379	252	25	213	698	462	71	1,435	84	30	6,188	2,320	490	22	37	8	111	.246	.310	.415	.725
8	Orioles	.335	1988	54	107	161	5,358	550	1,275	199	20	137	517	504	32	869	69	44	5,979	1,925	356	40	45	31	140	.238	.305	.359	.664
9	Browns	.338	1951	52	102	154	5,219	611	1,288	223	47	86	555	521	16	692	35	38	5,848	1,863	356	92			151	.247	.317	.357	.674
10	Browns	.344	1949	53	101	155	5,112	666	1,301	213	30	117	628	631	21	700	38	39	5,847	1,925	360	83			138	.254	.339	.377	.715
11	Browns	.344	1912	53	101	157	5,080	556	1,262	166	71	19	468	449	42	797	176	174	5,708	1,627	256	137				.248	.315	.320	.635
12	Brewers	.350	1901	48	89	139	4,795	641	1,250	192	66	26	513	325	46	387	176		5,288	1,652	284	122				.261	.314	.345	.658
13	Orioles	.351	1954	54	100	154	5,206	483	1,309	195	49	52	451	467	21	634	30	31	5,837	1,758	296	99	44		131	.251	.313	.338	.651
14	Browns	.351	1953	54	100	154	5,264	555	1,310	214	25	112	522	506	17	644	17	34	5,876	1,910	351	89			144	.249	.317	.363	.680
15	Browns	.353	1905	54	99	156	5,204	509	1,205	153	49	16	415	362	52	639	144		5,768	1,504	218	150				.232	.288	.289	.577
16	Browns	.362	1938	55	97	156	5,333	755	1,498	273	36	92	713	589	20	525	51	40	6,048	2,119	401	106				.281	.355	.397	.752
17	Browns	.364	1933	55	96	153	5,283	669	1,337	243	64	64	606	520	15	555	72	60	5,905	1,900	371	87				.253	.322	.360	.681
18	Orioles	.370	1955	57	97	156	5,257	540	1,263	177	39	54	503	562	19	740	34	46	5,935	1,680	270	70	27	31	127	.240	.314	.320	.634
19	Browns	.370	1917	57	97	155	5,091	511	1,250	183	63	15	425	405	31	540	157		5,693	1,604	261	166				.246	.305	.315	.620
20	Browns	.373	1913	57	96	155	5,031	528	1,193	179	73	18	422	449	43	775	209		5,664	1,572	270	141				.237	.305	.312	.618
21	Browns	.375	1936	57	95	155	5,391	804	1,502	299	66	79	761	625	19	630	62	20	6,107	2,170	444	72				.279	.356	.403	.758
22	Browns	.377	1950	58	96	154	5,163	684	1,269	235	43	106	642	691	20	742	39	40	5,971	1,908	384	97			138	.246	.337	.370	.707
23	Browns	.383	1947	59	95	154	5,145	564	1,238	189	52	90	526	583	15	663	69	49	5,819	1,801	331	76			118	.241	.320	.350	.670
24	Browns	.386	1948	59	94	155	5,303	671	1,438	251	62	63	625	578	19	571	63	44	6,013	2,002	376	113			131	.271	.345	.378	.722
25	Browns	.386	1927	59	94	155	5,217	724	1,442	263	59	55	657	449	42	417	90	66	5,900	1,988	377	192				.276	.339	.381	.720