Climate The Florida Keys Marathon International Airport 2020-2024

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

Calculated from historical METAR data of The Florida Keys Marathon International Airport (KMTH) between 2020 and 2024.

VFR conditions (%)

Month	Average	2024	2023	2022	2021	2020
January	89.1	77	95	83	93	91
February	88.4	74	94	85	92	91
March	86.8	93	89	87	98	93
April	95.1		90	97	97	94
May	92.9		91	94	96	91
June	92.0		87	89	96	97
July	93.4		95	88	94	95
August	94.6		87	96	96	99
September	92.8		91	90	93	93
October	93.1		87	88	97	94
November	91.0		88	87	89	91
December	89.8		81	91	98	92
Average	90.7	81.4	89.5	89.6	95.0	93.6

VFR conditions during daylight period

Percentage of observations where the VFR minimums for ceiling and visibility are met: visibility of 5 mi 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	96.0	90	99	94	100	95
February	93.4	82	99	91	100	96
March	91.7	99	97	97	99	99
April	98.9		98	99	100	100
May	98.4		100	99	99	96
June	97.0		94	95	98	99
July	97.2		99	90	98	98
August	97.8		93	99	99	100
September	97.1		97	97	98	96
October	97.7		98	94	98	98
November	97.6		94	98	96	98
December	95.1		88	97	100	96
Average	96.0	90.8	96.3	95.7	98.7	97.4

Marginal VFR conditions or better during daylight period

Percentage of observations where the MVFR minimums for ceiling and visibility are met: visibility of 3⅛ mi 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	21.9	2	26	24	23	25
February	23.8	0	29	26	26	27
March	25.0	12	29	28	27	28
April	29.8		31	30	29	31
May	30.7		31	31	31	30
June	32.1		33	32	31	32
July	32.7		35	32	31	32
August	32.9		34	34	32	33
September	31.9		33	33	31	32
October	30.2		30	30	30	30
November	27.7		28	30	25	28
December	24.6		16	27	27	24
Average	26.2	4.6	29.5	29.7	28.6	29.3

46th 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	16.3	0	20	18	18	19
February	17.7	0	23	19	21	21
March	18.5	10	22	22	22	23
April	23.8		25	24	22	26
May	24.5		25	25	25	24
June	25.2		24	26	25	26
July	26.7		29	25	25	26
August	26.6		28	28	27	26
September	25.3		25	27	25	25
October	24.8		25	24	24	26
November	21.0		18	25	17	22
December	18.6		7	23	22	18
Average	20.5	3.2	22.5	23.7	22.5	23.4

Average lowest temperature per day

The minimum temperature is typically observed just before sunrise.

Precipitation (%)

Month	Average	2024	2023	2022	2021	2020
January	1.9	3	2	2	0	1
February	2.5	5	1	4	1	5
March	1.0	2	3	1	0	0
April	1.4		2	1	0	0
May	3.6		1	3	1	7
June	2.8		3	7	2	2
July	2.7		1	3	4	5
August	2.6		6	1	4	0
September	4.7		5	6	3	6
October	5.1		4	6	3	8
November	3.3		5	3	6	7
December	4.3		16	2	1	1
Average	2.9	2.9	3.8	3.5	2.1	3.5

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	8.1	8	8	8	7	8
February	7.5	6	7	8	8	9
March	8.2	9	8	10	9	9
April	8.2		7	9	9	8
May	7.4		6	7	8	8
June	5.9		5	6	7	6
July	5.8		5	6	6	7
August	6.3		6	7	7	7
September	6.8		6	7	5	7
October	8.2		8	8	7	8
November	8.7		8	8	8	11
December	8.3		10	9	7	8
Average	7.4	7.7	6.8	7.4	7.3	7.9

46th 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	051°	059°	014°	037°	050°
February	007°	093°	058°	111°	072°
March	114°	085°	082°	083°	090°
April		111°	089°	089°	151°
May		076°	110°	093°	085°
June		195°	129°	119°	111°
July		116°	117°	119°	103°
August		114°	115°	107°	122°
September		082°	119°	085°	113°
October		042°	036°	073°	091°
November		048°	051°	025°	066°
December		044°	045°	068°	045°

Prevailing wind direction

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