The climate of Kobe, a Japanese city in the southern part of Honshu Island, in the Kansai region, is temperate humid, with quite mild winters, and hot, moist, and rainy summers. Like the rest of Japan, the city is affected by the monsoon circulation: in winter the northwest cold currents will prevail, while in summer they will be replaced by hot and humid currents of tropical origin.
Kobe is located on the coast, in the Seto Inland Sea, an area relatively protected both from the summer monsoon and from typhoons. The city is stretched along the coast, with a range of low mountains behind (the Rokko Mountains), while to the east it is practically merged with Osaka and Kyoto, in a large metropolitan area called Keihanshin.
In winter there are fairly mild periods, with highs above 10 °C (50 °F), alternating with cold periods, with wind and rain, highs around 5/7 °C (41/45 °F) or less, and possible falls of sleet or snow. Snowfalls, however, are light, as are nocturnal frosts.
Summers are hot and humid; there can be periods of good weather, with maximum temperatures around 35 °C (95 °F) or above, tropical nights and high humidity, but also periods of bad weather, due to the summer monsoon. August is the hottest month, both for the thermal inertia of the sea, and for the lower frequency of periods of bad weather.
Here are the average temperatures.
Average temperatures - Kobe

Kobe	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Kobe	J	F	M	A	M	J	J	A	S	O	N	D
Min (°C)	3	3	6	11	16	20	24	26	22	16	11	5
Max (°C)	9	10	13	19	23	27	30	32	28	23	17	12
Min (°F)	37	37	43	52	61	68	75	79	72	61	52	41
Max (°F)	48	50	55	66	73	81	86	90	82	73	63	54

The rains are quite abundant, as they amount to 1,200 millimetres (47 inches) per year; winter is undoubtedly the driest season, at least in quantity; the rainiest months are June and July, ie the first period of the rainy season (called Baiu). In August there is a certain decrease in rain frequency: on average, among the summer months, it is the hottest, as well as the driest and sunniest.
Here is the average precipitation.
Average precipitation - Kobe

Kobe	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Year
Kobe	J	F	M	A	M	J	J	A	S	O	N	D	Y
Prec. (mm)	40	55	95	100	150	180	150	90	145	100	65	40	1215
Prec. (in)	1.6	2.2	3.7	3.9	5.9	7.1	5.9	3.5	5.7	3.9	2.6	1.6	47.8
Days	6	7	11	10	11	12	11	7	10	8	6	6	106

From June to October (but especially from August to early October), Kobe may be affected by typhoons, the tropical cyclones of Southeast Asia, though this area of the Seto Inland Sea is relatively sheltered (however, in September 1934, the city was hit by a typhoon that caused a lot of damage).
The cherry blossoming in Kobe occurs around April the 3rd.
The amount of sunshine in Kobe, all in all is decent in winter, but it never becomes very good, however, there are two relative maxima, one in spring (April-May), and the other in August, after the Baiu rains.
Sunshine - Kobe

Kobe	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Kobe	J	F	M	A	M	J	J	A	S	O	N	D
Sun (hours)	5	5	5	6	6	5	6	7	5	5	5	5

The sea in Kobe is warm enough for swimming, with a temperature of 23 °C (73 °F) or more, from July to October, and it becomes pleasantly warm in August.
Sea temperature - Kobe

Kobe	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Kobe	J	F	M	A	M	J	J	A	S	O	N	D
Sea (°C)	17	15	16	17	19	22	25	27	26	23	21	19
Sea (°F)	63	59	61	63	66	72	77	81	79	73	70	66