Monthly Humidity Averages for Maine

The humidity averages for each month are listed below for places in Maine. The tables give the daily averages along with highest and lowest relative humidity levels.

Relative humidity measures the actual amount of moisture in the air as a percentage of the maximum amount of moisture the air can hold.

All the numbers here are averages for the years 1961 to 1990.

Average Humidity

In this table, the Daily number for the month or year is the average of humidity readings taken every three hours throughout the day. Morning percentages are for 7 am and Afternoon measures are for 4 pm local standard time.

Average relative humidity (%) for Caribou, Maine

Daily		Morning	Afternoon
70	January	75	66
71	February	74	62
71	March	76	59
74	April	75	56
69	May	74	52
68	June	78	54
77	July	83	58
79	August	86	60
82	September	87	61
82	October	86	64
85	November	85	73
79	December	80	73
76	Annual	80	61

Average relative humidity (%) for Portland, Maine

Daily		Morning	Afternoon
67	January	73	59
65	February	73	57
66	March	73	58
67	April	72	57
71	May	75	60
75	June	79	63
75	July	81	63
76	August	84	63
77	September	85	64
74	October	84	63
73	November	81	64
70	December	77	63
71	Annual	78	61

Highest and Lowest Humidity

Below are the monthly and yearly averages for maximum and minimum humidity levels in Maine. The hours when a month's highest and lowest humidity readings usually occur are given in local standard time.

Daily high and low relative humidity (%) averages in Caribou, Maine

High	Time		Low	Time
74.8	7 am	January	64.9	1 pm
75.5	4 am	February	61.4	1 pm
79.2	4 am	March	58.8	4 pm
84.4	4 am	April	55.5	4 pm
84.8	4 am	May	51.5	4 pm
86.4	4 am	June	54.3	4 pm
92.5	4 am	July	57.9	4 pm
95.0	4 am	August	60.0	4 pm
93.7	4 am	September	61.2	4 pm
90.8	4 am	October	62.6	1 pm
89.0	4 am	November	70.9	1 pm
83.2	4 am	December	70.5	1 pm
85.6	4 am	Annual	61.1	1 pm

Daily high and low relative humidity (%) averages in Portland, Maine

High	Time		Low	Time
73.4	7 am	January	57.9	1 pm
73.1	7 am	February	55.9	1 pm
74.2	4 am	March	56.0	1 pm
78.6	4 am	April	53.8	1 pm
85.2	4 am	May	57.6	1 pm
89.5	4 am	June	60.4	1 pm
90.3	4 am	July	60.0	1 pm
90.2	4 am	August	60.0	1 pm
89.2	4 am	September	59.9	1 pm
84.7	4 am	October	57.8	1 pm
80.5	7 am	November	60.7	1 pm
77.2	7 am	December	60.5	1 pm
82.0	4 am	Annual	58.4	1 pm