Millinocket
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Millinocket clear sky chart from 2005-11-06 to 2026-04-02.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	18% 9% 3 7% 5% 5% 5% 4 6% 7% 33%	130759
	Night	17% 9% 3 8% 5% 5% 5% 4 5% 6% 33%	131150
Transparency	Day	49% 6% 12% 20% 11% 1	134248
	Night	49% 6% 12% 20% 11% 1	135751
Seeing	Day	25% 17% 30% 19% 8% 2	17563
	Night	23% 14% 31% 24% 7%	25929

By Month

Percentage Cloud Cover NE (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	12% 11% 4 11% 6% 5% 4 3 5% 5% 34%	4475
	11th to 20th	Day	14% 12% 5% 11% 7% 6% 5% 4 5% 6% 26%	4650
	21st to end	Day	7% 10% 4 8% 5% 5% 6% 5% 6% 7% 38%	5124
February	1st to 10th	Day	12% 12% 5% 8% 8% 6% 5% 4 5% 6% 29%	1879
	11th to 20th	Day	13% 10% 5% 10% 8% 5% 5% 3 5% 6% 31%	1927
	21st to end	Day	13% 12% 3 9% 6% 5% 4 4 5% 6% 33%	1730
March	1st to 10th	Day	23% 14% 3 8% 4 4 4 3 4 5% 27%	4612
	11th to 20th	Day	19% 14% 3 8% 5% 4 4 3 5% 6% 28%	5090
	21st to end	Day	24% 11% 4 7% 5% 4 4 3 5% 6% 27%	5587
April	1st to 10th	Day	20% 11% 3 8% 5% 4 5% 3 5% 6% 29%	2396
	11th to 20th	Day	19% 10% 3 6% 4 4 5% 3 5% 6% 34%	2565
	21st to end	Day	24% 10% 3 6% 4 4 3 3 4 6% 34%	2600
May	1st to 10th	Day	27% 10% 3 7% 5% 4 5% 4 5% 5% 26%	5886
	11th to 20th	Day	26% 8% 2 6% 5% 4 5% 5% 5% 6% 28%	5942
	21st to end	Day	19% 8% 3 7% 5% 6% 5% 4 6% 7% 29%	7379
June	1st to 10th	Day	22% 8% 3 8% 5% 4 5% 3 6% 7% 29%	3000
	11th to 20th	Day	18% 8% 2 6% 5% 4 4 4 6% 8% 35%	3000
	21st to end	Day	24% 7% 3 6% 5% 5% 5% 4 6% 7% 28%	3000
July	1st to 10th	Day	13% 7% 3 7% 6% 5% 6% 5% 8% 10% 29%	6803
	11th to 20th	Day	14% 7% 3 7% 4 5% 5% 4 6% 8% 36%	6360
	21st to end	Day	12% 7% 2 6% 4 5% 5% 4 6% 9% 40%	6926
August	1st to 10th	Day	15% 6% 2 7% 5% 5% 5% 5% 7% 9% 33%	4235
	11th to 20th	Day	15% 8% 3 7% 5% 5% 6% 5% 7% 8% 32%	4175
	21st to end	Day	14% 6% 2 7% 4 4 5% 4 6% 9% 40%	4675
September	1st to 10th	Day	12% 5% 2 6% 5% 4 4 3 6% 7% 47%	2326
	11th to 20th	Day	14% 5% 3 5% 4 4 4 3 5% 6% 49%	2200
	21st to end	Day	16% 7% 3 6% 3 4 4 3 5% 7% 42%	2200
October	1st to 10th	Day	17% 6% 2 7% 4 4 5% 3 4 7% 41%	2131
	11th to 20th	Day	20% 9% 2 7% 4 4 4 4 5% 6% 33%	1967
	21st to end	Day	22% 12% 3 7% 4 4 4 3 5% 6% 29%	1980
November	1st to 10th	Day	18% 10% 3 8% 5% 4 5% 4 4 6% 34%	1851
	11th to 20th	Day	18% 10% 3 7% 5% 5% 4 3 5% 6% 34%	1778
	21st to end	Day	21% 10% 3 8% 5% 4 3 4 5% 6% 31%	1680
December	1st to 10th	Day	18% 12% 3 6% 5% 5% 5% 4 6% 7% 28%	2389
	11th to 20th	Day	19% 8% 3 6% 5% 4 5% 4 4 6% 35%	2688
	21st to end	Day	19% 11% 4 7% 3 5% 5% 4 5% 6% 31%	3553
January	1st to 10th	Night	11% 11% 4 12% 7% 6% 5% 4 5% 5% 30%	8412
	11th to 20th	Night	13% 13% 5% 12% 7% 7% 6% 4 6% 6% 21%	8235
	21st to end	Night	7% 9% 4 8% 6% 7% 6% 5% 6% 7% 35%	9057
February	1st to 10th	Night	12% 13% 4 9% 5% 5% 5% 4 6% 6% 32%	2740
	11th to 20th	Night	11% 11% 4 9% 7% 6% 5% 4 5% 6% 32%	2576
	21st to end	Night	14% 12% 4 8% 4 4 3 3 5% 5% 36%	2076
March	1st to 10th	Night	24% 11% 4 9% 5% 4 4 3 4 4 27%	5448
	11th to 20th	Night	18% 12% 3 8% 4 4 5% 4 6% 7% 29%	5089
	21st to end	Night	25% 11% 2 7% 4 3 5% 4 6% 7% 26%	5587
April	1st to 10th	Night	22% 13% 3 6% 4 4 4 3 4 4 32%	2023
	11th to 20th	Night	20% 9% 2 7% 4 4 3 3 5% 6% 37%	1783
	21st to end	Night	24% 9% 2 6% 5% 4 4 3 5% 7% 31%	1800
May	1st to 10th	Night	26% 9% 3 8% 5% 5% 4 3 4 6% 27%	4054
	11th to 20th	Night	24% 8% 3 7% 5% 5% 5% 4 6% 7% 27%	3995
	21st to end	Night	17% 7% 3 6% 4 4 5% 4 5% 8% 37%	3515
June	1st to 10th	Night	22% 9% 3 7% 5% 4 5% 4 5% 7% 30%	1400
	11th to 20th	Night	15% 7% 2 8% 4 5% 5% 4 5% 9% 36%	1400
	21st to end	Night	24% 8% 3 6% 4 4 4 3 6% 7% 31%	1400
July	1st to 10th	Night	13% 7% 2 7% 5% 4 6% 4 6% 9% 36%	3160
	11th to 20th	Night	16% 9% 3 7% 4 4 4 4 6% 7% 39%	3599
	21st to end	Night	10% 5% 2 6% 4 5% 5% 4 6% 9% 43%	3926
August	1st to 10th	Night	20% 5% 3 7% 5% 6% 5% 4 6% 7% 32%	2881
	11th to 20th	Night	12% 9% 3 7% 5% 4 5% 4 7% 8% 34%	2872
	21st to end	Night	13% 7% 3 6% 4 3 3 3 4 6% 48%	3223
September	1st to 10th	Night	13% 5% 1 4 3 3 4 4 5% 8% 49%	2070
	11th to 20th	Night	13% 6% 1 4 3 3 3 4 4 7% 50%	2200
	21st to end	Night	17% 7% 2 6% 4 3 4 3 5% 7% 43%	2200
October	1st to 10th	Night	18% 5% 3 5% 4 4 3 3 5% 7% 42%	2268
	11th to 20th	Night	18% 7% 3 7% 5% 4 4 3 5% 6% 38%	2430
	21st to end	Night	23% 10% 3 6% 4 3 4 3 4 6% 34%	2860
November	1st to 10th	Night	19% 9% 2 7% 4 4 4 4 5% 7% 34%	2667
	11th to 20th	Night	18% 9% 3 7% 5% 4 4 4 5% 5% 36%	2840
	21st to end	Night	19% 9% 3 7% 5% 5% 4 4 6% 7% 31%	2940
December	1st to 10th	Night	16% 11% 3 8% 6% 6% 6% 4 6% 6% 28%	5016
	11th to 20th	Night	22% 9% 3 6% 5% 5% 4 3 4 6% 32%	5741
	21st to end	Night	20% 11% 3 7% 4 4 4 3 5% 5% 34%	7667

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	51% 4 11% 23% 9% 1	4476
	11th to 20th	Day	56% 5% 9% 20% 9% 1	4680
	21st to end	Day	43% 7% 9% 20% 20% 2	5124
February	1st to 10th	Day	54% 5% 10% 18% 10% 3	1879
	11th to 20th	Day	53% 5% 11% 17% 12% 1	1935
	21st to end	Day	50% 6% 9% 20% 11% 4	1730
March	1st to 10th	Day	60% 4 7% 9% 16% 4	4615
	11th to 20th	Day	55% 7% 15% 13% 9% 1	5090
	21st to end	Day	57% 4 6% 18% 13% 3	5587
April	1st to 10th	Day	56% 4 10% 15% 12% 3	2396
	11th to 20th	Day	50% 5% 10% 20% 14% 1	2565
	21st to end	Day	51% 5% 8% 19% 12% 4	2600
May	1st to 10th	Day	59% 6% 9% 17% 8% 1	5897
	11th to 20th	Day	54% 7% 13% 17% 6% 3	5946
	21st to end	Day	50% 8% 12% 16% 12% 2	7379
June	1st to 10th	Day	53% 7% 13% 18% 9% 1	3000
	11th to 20th	Day	47% 6% 11% 21% 13% 2	3000
	21st to end	Day	54% 8% 11% 17% 9% 1	3000
July	1st to 10th	Day	47% 8% 17% 19% 8%	6728
	11th to 20th	Day	45% 7% 12% 26% 10%	6285
	21st to end	Day	40% 7% 13% 30% 10%	6728
August	1st to 10th	Day	46% 8% 15% 25% 7%	4222
	11th to 20th	Day	47% 8% 17% 21% 7%	4214
	21st to end	Day	40% 7% 14% 25% 14% 1	4675
September	1st to 10th	Day	36% 7% 13% 27% 17% 1	2326
	11th to 20th	Day	36% 5% 12% 29% 17% 1	2200
	21st to end	Day	41% 5% 10% 28% 14% 1	2200
October	1st to 10th	Day	51% 5% 12% 23% 9%	3469
	11th to 20th	Day	46% 6% 11% 29% 8%	3183
	21st to end	Day	42% 5% 16% 21% 16%	3180
November	1st to 10th	Day	51% 6% 13% 18% 11% 1	1851
	11th to 20th	Day	49% 6% 12% 19% 11% 2	1778
	21st to end	Day	53% 6% 15% 19% 7% 1	1680
December	1st to 10th	Day	53% 6% 16% 13% 11%	2389
	11th to 20th	Day	48% 6% 12% 16% 13% 6%	2688
	21st to end	Day	52% 6% 12% 15% 12% 4	3553
January	1st to 10th	Night	54% 6% 12% 18% 10%	8412
	11th to 20th	Night	60% 7% 11% 14% 8% 1	8280
	21st to end	Night	45% 6% 9% 20% 17% 2	9057
February	1st to 10th	Night	52% 6% 10% 19% 11% 2	2740
	11th to 20th	Night	51% 6% 12% 17% 12% 2	2579
	21st to end	Night	49% 5% 8% 21% 14% 3	2076
March	1st to 10th	Night	59% 5% 7% 14% 12% 3	5458
	11th to 20th	Night	52% 7% 18% 14% 7% 1	5090
	21st to end	Night	55% 5% 6% 19% 14% 1	5587
April	1st to 10th	Night	55% 5% 7% 14% 15% 4	2023
	11th to 20th	Night	48% 5% 10% 20% 15% 3	1783
	21st to end	Night	53% 6% 10% 16% 13% 3	1800
May	1st to 10th	Night	56% 7% 11% 16% 9%	4060
	11th to 20th	Night	52% 10% 11% 20% 6% 1	3996
	21st to end	Night	42% 9% 15% 21% 12% 1	3516
June	1st to 10th	Night	52% 7% 11% 20% 9% 1	1400
	11th to 20th	Night	45% 6% 14% 21% 12% 1	1400
	21st to end	Night	53% 6% 13% 18% 10% 1	1400
July	1st to 10th	Night	43% 7% 18% 23% 9%	3125
	11th to 20th	Night	44% 7% 13% 30% 6%	3552
	21st to end	Night	37% 7% 17% 29% 10%	3809
August	1st to 10th	Night	51% 6% 14% 23% 6%	2871
	11th to 20th	Night	45% 9% 17% 21% 8% 1	2899
	21st to end	Night	38% 6% 15% 24% 17% 1	3223
September	1st to 10th	Night	32% 7% 15% 32% 13% 1	2070
	11th to 20th	Night	34% 5% 13% 30% 17% 1	2200
	21st to end	Night	41% 7% 10% 26% 15% 1	2200
October	1st to 10th	Night	47% 5% 11% 24% 12%	3710
	11th to 20th	Night	42% 5% 11% 30% 12%	3953
	21st to end	Night	42% 5% 16% 22% 14% 1	4610
November	1st to 10th	Night	47% 7% 13% 22% 10% 1	2667
	11th to 20th	Night	49% 6% 13% 19% 12% 2	2840
	21st to end	Night	51% 7% 15% 16% 10% 1	2940
December	1st to 10th	Night	54% 6% 12% 21% 7%	5016
	11th to 20th	Night	52% 5% 10% 18% 15% 1	5742
	21st to end	Night	52% 5% 10% 17% 14% 2	7667

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	30% 24% 28% 16% 2	220
	11th to 20th	Day	33% 22% 29% 12% 4	220
	21st to end	Day	20% 21% 38% 14% 7%	242
February	1st to 10th	Day	23% 20% 32% 20% 5% 1	419
	11th to 20th	Day	26% 24% 32% 14% 3	470
	21st to end	Day	26% 22% 33% 17% 2	446
March	1st to 10th	Day	30% 22% 32% 13% 2	540
	11th to 20th	Day	27% 24% 29% 15% 5% 1	540
	21st to end	Day	31% 20% 28% 14% 5% 2	594
April	1st to 10th	Day	36% 19% 27% 13% 5% 1	504
	11th to 20th	Day	32% 21% 29% 11% 7% 1	492
	21st to end	Day	33% 18% 32% 11% 4 2	500
May	1st to 10th	Day	32% 16% 30% 17% 4 1	503
	11th to 20th	Day	28% 18% 30% 17% 6% 2	527
	21st to end	Day	22% 20% 32% 20% 5% 1	756
June	1st to 10th	Day	25% 16% 30% 19% 9% 1	730
	11th to 20th	Day	24% 13% 29% 21% 12% 1	730
	21st to end	Day	27% 11% 30% 21% 10% 1	730
July	1st to 10th	Day	18% 11% 34% 25% 10% 2	716
	11th to 20th	Day	18% 9% 39% 21% 10% 2	524
	21st to end	Day	16% 9% 36% 28% 9% 3	576
August	1st to 10th	Day	17% 8% 30% 30% 11% 3	526
	11th to 20th	Day	16% 11% 27% 28% 14% 4	519
	21st to end	Day	18% 12% 29% 24% 15% 3	583
September	1st to 10th	Day	15% 14% 28% 26% 13% 4	530
	11th to 20th	Day	18% 10% 27% 22% 17% 5%	530
	21st to end	Day	18% 15% 29% 21% 11% 5%	530
October	1st to 10th	Day	19% 15% 27% 21% 13% 4	491
	11th to 20th	Day	27% 17% 30% 16% 8% 2	420
	21st to end	Day	31% 18% 26% 21% 4	462
November	1st to 10th	Day	31% 17% 26% 20% 6%	425
	11th to 20th	Day	28% 18% 31% 15% 6% 1	430
	21st to end	Day	29% 23% 27% 16% 4	430
December	1st to 10th	Day	28% 16% 33% 19% 5%	246
	11th to 20th	Day	33% 24% 29% 12% 2	220
	21st to end	Day	31% 24% 24% 17% 5%	242
January	1st to 10th	Night	23% 17% 34% 22% 4	873
	11th to 20th	Night	24% 19% 33% 20% 4	840
	21st to end	Night	16% 19% 38% 22% 4	924
February	1st to 10th	Night	20% 19% 35% 22% 4	840
	11th to 20th	Night	22% 20% 38% 17% 3	823
	21st to end	Night	23% 16% 35% 23% 2	692
March	1st to 10th	Night	24% 17% 36% 21% 2	840
	11th to 20th	Night	24% 17% 33% 20% 6%	840
	21st to end	Night	23% 17% 32% 21% 6%	924
April	1st to 10th	Night	31% 14% 34% 18% 4	805
	11th to 20th	Night	24% 15% 34% 21% 6%	599
	21st to end	Night	33% 13% 30% 20% 5%	600
May	1st to 10th	Night	27% 10% 33% 25% 4 1	600
	11th to 20th	Night	24% 14% 31% 23% 7%	580
	21st to end	Night	22% 10% 34% 27% 7%	433
June	1st to 10th	Night	25% 7% 30% 29% 8% 1	400
	11th to 20th	Night	18% 9% 30% 34% 10%	400
	21st to end	Night	27% 7% 27% 33% 7%	400
July	1st to 10th	Night	17% 4 33% 35% 10% 1	390
	11th to 20th	Night	19% 4 30% 35% 12%	388
	21st to end	Night	18% 6% 26% 37% 13%	438
August	1st to 10th	Night	17% 7% 24% 36% 15%	576
	11th to 20th	Night	16% 6% 24% 36% 17% 1	592
	21st to end	Night	15% 8% 26% 36% 14% 1	660
September	1st to 10th	Night	16% 8% 30% 30% 15% 1	779
	11th to 20th	Night	17% 9% 24% 33% 15% 2	800
	21st to end	Night	21% 9% 30% 27% 13% 1	800
October	1st to 10th	Night	21% 11% 28% 26% 13% 1	800
	11th to 20th	Night	22% 12% 30% 24% 11% 1	800
	21st to end	Night	29% 15% 28% 23% 5%	880
November	1st to 10th	Night	26% 14% 30% 22% 7%	820
	11th to 20th	Night	24% 16% 29% 22% 8% 1	898
	21st to end	Night	27% 17% 30% 22% 4	950
December	1st to 10th	Night	28% 12% 34% 21% 4 1	950
	11th to 20th	Night	26% 21% 29% 21% 3	950
	21st to end	Night	28% 15% 33% 19% 4	1045

Page generated at 2026-03-30 02:18:45. Version ac07

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