Climate Hiroshima Garden City Hakushima Johoku West Tower Helipad 2020-2024

Climate and trends: average temperature, flight conditions, precipitation, wind speed and direction.

Calculated from historical METAR data of Iwakuni Kintaikyo Airport / Marine Corps Air Station Iwakuni (RJOI) between 2020 and 2024.

VFR conditions (%)

Month	Average	2024	2023	2022	2021	2020
January	91.4	92	88	95
February	84.8	81	82	92
March	78.0	77	87	71
April	81.8		78	86
May	80.2		73	89
June	74.3		65	85
July	86.0		84	89		0
August	96.6		96	97	100
September	92.0		96	88	92
October	97.3		96	100	96	0
November	94.4		95	92	97
December	96.6		93	100	98
Average	75.5	82.8	85.0	89.3	95.8

16th best VFR conditions of Japan

VFR conditions during daylight period

Percentage of observations where the VFR minimums for ceiling and visibility are met: visibility of 8 km or more and a ceiling of 3,000 ft or more. Only observations between sunrise and sunset are taken into account.

Marginal VFR conditions (%)

Month	Average	2024	2023	2022	2021	2020
January	95.4	98	93	96
February	93.1	89	91	99
March	84.2	89	91	74
April	88.5		85	93
May	87.1		82	94
June	85.9		80	93
July	94.6		94	95		100
August	98.9		99	99	100
September	97.7		99	96	98
October	100.0		100	100	100	0
November	97.6		99	96	98
December	98.9		99	100	98
Average	96.0	91.6	91.7	93.9	98.7	100.0

Marginal VFR conditions or better during daylight period

Percentage of observations where the MVFR minimums for ceiling and visibility are met: visibility of 5 km or more and a ceiling of 1,000 ft or more. Only observations between sunrise and sunset are taken into account.

Maximum temperatures (°C)

Month	Average	2024	2023	2022	2021	2020
January	10.3	11	10	10
February	10.7	12	11	9
March	14.8	14	16	15
April	19.2		19	19
May	22.9		23	23
June	26.1		26	27
July	30.3		31	30		27
August	32.3		33	32	31
September	28.9		31	29	28
October	23.7		24	23	24	22
November	18.6		19	20	18
December	12.1		13	12	12
Average	21.1	12.3	21.2	21.0	20.7	24.4

26th highest temperature of Japan

Average highest temperature per day

The maximum temperature is typically observed some hours after noon.

Minimum temperatures (°C)

Month	Average	2024	2023	2022	2021	2020
January	3.2	4	3	3
February	3.2	6	2	2
March	4.8	7	4	4
April	10.4		8	13
May	10.1		4	16
June	15.2		9	21
July	25.0		25	26		27
August	26.7		27	26	25
September	23.6		25	24	22
October	16.0		15	16	16	22
November	10.4		11	11	10
December	5.2		6	5	5
Average	16.1	5.5	11.6	14.1	13.8	24.4

40th lowest temperature of Japan

Average lowest temperature per day

The minimum temperature is typically observed just before sunrise.

Precipitation (%)

Month	Average	2024	2023	2022	2021	2020
January	7.7	8	8	7
February	13.9	17	14	11
March	11.4	18	7	10
April	16.0		19	13
May	12.9		15	10
June	18.5		20	17
July	11.3		12	10		100
August	6.0		9	4	0
September	8.3		5	10	10
October	2.1		2	4	1	0
November	4.9		4	5	6
December	5.5		6	4	6
Average	23.2	14.3	10.5	9.1	5.5	100.0

Precipitation during daylight period

Percentage of observations with observed rain, drizzle, snow or hail. Only observations between sunrise and sunset are taken into account.

Wind speed (knots)

Month	Average	2024	2023	2022	2021	2020
January	7.3	8	7	7
February	7.2	8	6	8
March	6.1	8	5	6
April	7.3		7	7
May	6.2		6	6
June	6.0		5	7
July	6.7		7	7		5
August	7.4		7	8	6
September	6.3		6	7	6
October	7.4		8	7	7	0
November	6.1		7	6	6
December	7.2		7	7	8
Average	6.4	7.6	6.4	6.9	6.6	5.0

26th highest wind speed of Japan

Average wind speed

Excluding wind gusts. Only observations between sunrise and sunset are taken into account.

Prevailing wind direction

Month	2024	2023	2022	2021	2020
January	326°	298°	325°
February	042°	041°	284°
March	049°	130°	141°
April		158°	127°
May		133°	146°
June		141°	152°
July		166°	160°		180°
August		146°	176°	139°
September		141°	069°	118°
October		045°	042°	058°	360°
November		267°	022°	271°
December		303°	310°	285°

Prevailing wind direction

Average wind direction, weighed by wind speed. Only observations between sunrise and sunset are taken into account.