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
Reference

World Data Center for Meteorology. Climate of the World.

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