Climate Northwest Field 2020-2024

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

Calculated from historical METAR data of Andersen Air Force Base (PGUA) between 2020 and 2024.

VFR conditions (%)

Month	Average	2024	2023	2022	2021	2020
January	54.9	47	41	53	91	62
February	57.2	53	41	56	92	69
March	57.5	50	39	40	86	72
April	52.4	43	37	33	79	67
May	58.3		39	37	72	69
June	69.7		55	58	90	74
July	64.6		51	55	86	74
August	64.7		63	58	83	70
September	65.2		62	60	70	78
October	59.6		49	51	76	79
November	60.4		53	48	69	72
December	55.4		49	44	77	58
Average	61.2	48.0	47.8	49.2	80.7	69.9

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	91.2	90	83	88	100	99
February	92.5	95	87	96	99	87
March	95.6	91	94	99	100	97
April	94.5	96	91	91	100	99
May	97.4		92	100	99	95
June	96.6		92	98	98	99
July	96.1		92	96	97	99
August	93.8		88	94	97	99
September	91.9		85	91	93	97
October	93.0		90	90	94	96
November	95.1		91	96	93	99
December	95.1		92	95	97	96
Average	94.7	92.7	89.6	94.5	97.3	96.8

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	28.2	28	28	28	29	28
February	28.4	28	29	29	30	28
March	28.9	29	29	29	30	28
April	29.3	30	29	29	30	29
May	29.8		29	30	30	30
June	30.0		29	30	30	30
July	29.9		30	29	30	30
August	29.8		30	30	29	30
September	29.5		30	30	29	30
October	29.4		30	29	29	29
November	29.4		30	30	29	29
December	28.9		29	29	29	30
Average	29.2	28.7	29.2	29.1	29.3	29.1

75th highest temperature of United States

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	24.5	25	25	24	25	25
February	24.2	24	23	25	25	24
March	24.0	24	24	25	24	25
April	24.8	25	25	25	25	25
May	25.3		25	25	26	26
June	25.3		26	25	26	26
July	25.1		24	25	25	26
August	24.8		25	24	25	26
September	24.6		25	25	24	25
October	24.5		25	24	24	25
November	25.5		25	25	26	26
December	25.2		25	25	25	25
Average	24.8	24.3	24.8	24.6	24.8	25.2

Average lowest temperature per day

The minimum temperature is typically observed just before sunrise.

Precipitation (%)

Month	Average	2024	2023	2022	2021	2020
January	7.9	12	12	11	3	3
February	6.3	6	9	4	2	7
March	4.6	8	7	4	1	2
April	6.1	6	12	6	1	2
May	4.2		7	5	3	3
June	5.6		8	10	2	2
July	10.9		14	17	10	3
August	14.1		23	10	14	5
September	14.4		21	16	12	17
October	13.1		14	22	9	5
November	7.5		9	10	13	3
December	7.0		11	10	9	3
Average	7.7	8.1	12.1	10.4	6.6	4.4

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	13.8	14	13	14	13	14
February	14.7	15	15	16	13	16
March	13.0	13	12	13	12	13
April	12.8	14	13	15	9	13
May	11.3		11	12	13	12
June	10.1		10	10	9	12
July	9.5		9	10	10	10
August	8.8		9	9	9	9
September	8.5		9	9	9	7
October	9.6		11	9	8	9
November	12.1		13	11	12	12
December	13.8		15	13	13	14
Average	11.8	14.0	11.7	11.4	10.8	11.7

75th highest wind speed of United States

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	061°	105°	075°	090°	083°
February	056°	103°	072°	099°	077°
March	064°	099°	096°	090°	088°
April	074°	090°	105°	128°	098°
May		082°	096°	099°	107°
June		072°	108°	120°	104°
July		092°	125°	120°	113°
August		231°	125°	115°	116°
September		182°	172°	111°	132°
October		096°	142°	129°	119°
November		083°	088°	093°	095°
December		069°	104°	087°	093°

Prevailing wind direction

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