Minot
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Minot clear sky chart from 2005-11-06 to 2025-04-11.

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	9% 8% 3 8% 5% 5% 5% 4 6% 7% 39%	116821
	Night	8% 9% 3 9% 6% 5% 5% 4 6% 7% 39%	120253
Transparency	Day	42% 6% 15% 25% 11% 1	116560
	Night	43% 6% 15% 24% 11% 1	120104
Seeing	Day	13% 10% 32% 29% 14% 3	16648
	Night	12% 9% 35% 33% 10% 1	26797

By Month

Percentage Cloud Cover SW (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	3 11% 6% 15% 11% 10% 7% 4 6% 6% 21%	3500
	11th to 20th	Day	3 7% 4 13% 8% 9% 13% 9% 10% 7% 17%	3640
	21st to end	Day	5% 9% 6% 15% 8% 5% 5% 4 5% 5% 34%	4004
February	1st to 10th	Day	8% 14% 7% 11% 7% 6% 5% 3 6% 5% 27%	1600
	11th to 20th	Day	7% 12% 4 11% 9% 7% 6% 4 6% 7% 26%	1860
	21st to end	Day	6% 12% 5% 13% 8% 6% 6% 4 4 6% 30%	1650
March	1st to 10th	Day	8% 10% 5% 11% 6% 4 4 3 5% 6% 37%	4500
	11th to 20th	Day	6% 11% 6% 12% 7% 6% 5% 4 6% 8% 27%	4755
	21st to end	Day	12% 17% 7% 13% 6% 4 4 3 4 6% 24%	5780
April	1st to 10th	Day	9% 10% 3 7% 6% 5% 4 4 6% 7% 38%	2400
	11th to 20th	Day	15% 12% 4 9% 5% 5% 5% 4 5% 5% 32%	2368
	21st to end	Day	17% 8% 3 7% 5% 5% 5% 4 6% 6% 36%	2470
May	1st to 10th	Day	18% 8% 3 7% 5% 4 4 4 5% 7% 35%	4275
	11th to 20th	Day	14% 7% 2 7% 5% 5% 5% 4 7% 7% 38%	4388
	21st to end	Day	17% 6% 2 6% 5% 4 4 4 6% 7% 40%	5079
June	1st to 10th	Day	12% 6% 2 5% 5% 5% 4 3 5% 8% 44%	2850
	11th to 20th	Day	11% 5% 2 6% 5% 5% 5% 5% 8% 9% 39%	2850
	21st to end	Day	9% 5% 2 6% 4 4 5% 5% 7% 9% 44%	2850
July	1st to 10th	Day	7% 4 2 5% 4 4 6% 5% 8% 11% 46%	4728
	11th to 20th	Day	4 4 1 4 3 3 4 4 7% 9% 58%	4430
	21st to end	Day	5% 3 1 4 4 4 5% 5% 6% 10% 54%	4802
August	1st to 10th	Day	11% 4 2 5% 4 4 4 4 6% 8% 48%	4411
	11th to 20th	Day	9% 5% 2 6% 4 4 5% 5% 7% 9% 44%	4108
	21st to end	Day	8% 4 2 5% 3 3 3 3 5% 7% 56%	4385
September	1st to 10th	Day	10% 5% 1 5% 3 3 4 3 5% 6% 55%	2280
	11th to 20th	Day	11% 5% 2 5% 3 3 4 3 5% 8% 51%	2138
	21st to end	Day	14% 5% 2 5% 3 3 3 3 4 5% 52%	2090
October	1st to 10th	Day	10% 5% 2 5% 3 3 4 3 5% 6% 55%	3432
	11th to 20th	Day	8% 7% 2 5% 4 3 3 3 5% 9% 51%	2842
	21st to end	Day	9% 10% 3 8% 4 5% 4 4 6% 6% 40%	3091
November	1st to 10th	Day	13% 12% 3 8% 4 4 4 3 5% 5% 37%	1763
	11th to 20th	Day	9% 11% 4 11% 6% 5% 4 3 5% 6% 35%	1671
	21st to end	Day	7% 13% 5% 10% 6% 5% 5% 3 6% 7% 33%	1400
December	1st to 10th	Day	5% 14% 6% 14% 7% 5% 6% 4 6% 6% 27%	2290
	11th to 20th	Day	7% 15% 6% 14% 6% 6% 6% 4 5% 6% 23%	2643
	21st to end	Day	6% 9% 5% 13% 7% 4 4 4 5% 5% 39%	3498
January	1st to 10th	Night	5% 11% 5% 14% 11% 8% 7% 5% 6% 5% 25%	6450
	11th to 20th	Night	4 8% 3 11% 8% 10% 9% 7% 10% 6% 25%	6340
	21st to end	Night	5% 10% 5% 13% 7% 5% 5% 4 5% 6% 34%	6974
February	1st to 10th	Night	7% 13% 6% 11% 8% 5% 6% 6% 6% 7% 26%	2800
	11th to 20th	Night	6% 12% 4 11% 6% 6% 6% 4 5% 6% 33%	2442
	21st to end	Night	7% 9% 4 9% 6% 4 5% 5% 5% 6% 39%	1980
March	1st to 10th	Night	8% 11% 4 11% 6% 4 4 3 5% 6% 38%	5374
	11th to 20th	Night	7% 10% 4 10% 6% 5% 5% 4 7% 9% 34%	5215
	21st to end	Night	8% 15% 6% 12% 5% 5% 4 4 5% 6% 30%	5162
April	1st to 10th	Night	7% 9% 3 7% 5% 4 4 4 5% 9% 42%	2000
	11th to 20th	Night	12% 12% 3 7% 4 5% 4 4 6% 7% 35%	1765
	21st to end	Night	15% 8% 2 7% 4 3 4 4 5% 8% 39%	1710
May	1st to 10th	Night	14% 7% 2 7% 5% 4 5% 4 7% 6% 38%	2680
	11th to 20th	Night	14% 6% 2 6% 5% 4 5% 4 6% 8% 40%	2517
	21st to end	Night	15% 5% 2 6% 5% 5% 4 3 6% 8% 42%	2492
June	1st to 10th	Night	11% 3 2 5% 5% 4 5% 5% 8% 8% 45%	1330
	11th to 20th	Night	11% 5% 2 5% 5% 4 5% 4 6% 9% 46%	1330
	21st to end	Night	7% 4 1 5% 4 5% 4 5% 8% 11% 47%	1330
July	1st to 10th	Night	5% 3 1 5% 4 4 5% 5% 7% 12% 50%	2238
	11th to 20th	Night	6% 3 2 4 3 3 4 4 6% 9% 55%	2540
	21st to end	Night	4 3 1 4 3 4 5% 4 7% 9% 56%	2761
August	1st to 10th	Night	6% 4 2 6% 3 3 4 3 6% 8% 55%	2528
	11th to 20th	Night	5% 5% 1 5% 4 5% 5% 4 6% 10% 50%	2731
	21st to end	Night	7% 3 1 3 3 3 3 3 5% 7% 62%	3280
September	1st to 10th	Night	9% 3 2 4 3 3 3 3 5% 6% 60%	1900
	11th to 20th	Night	9% 5% 2 5% 4 4 4 4 5% 7% 52%	2042
	21st to end	Night	14% 6% 1 6% 3 3 3 3 4 7% 50%	2090
October	1st to 10th	Night	8% 6% 2 5% 4 3 4 3 5% 7% 55%	3527
	11th to 20th	Night	8% 6% 2 6% 4 4 4 4 6% 8% 47%	4054
	21st to end	Night	8% 8% 3 7% 5% 4 5% 3 5% 6% 47%	4467
November	1st to 10th	Night	12% 10% 3 6% 6% 5% 4 4 5% 7% 39%	2535
	11th to 20th	Night	7% 12% 4 10% 6% 6% 4 4 5% 7% 34%	2725
	21st to end	Night	8% 11% 5% 10% 6% 4 4 4 5% 7% 37%	3000
December	1st to 10th	Night	5% 12% 5% 13% 8% 7% 6% 4 5% 7% 29%	4900
	11th to 20th	Night	8% 12% 4 11% 8% 7% 7% 4 5% 6% 27%	5564
	21st to end	Night	6% 9% 4 13% 7% 7% 5% 4 5% 6% 34%	7480

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	61% 7% 13% 14% 5%	3501
	11th to 20th	Day	58% 6% 14% 13% 8%	3640
	21st to end	Day	53% 4 18% 19% 6%	4004
February	1st to 10th	Day	57% 5% 11% 20% 7% 1	1600
	11th to 20th	Day	56% 6% 11% 16% 10%	1870
	21st to end	Day	54% 5% 15% 17% 8% 1	1650
March	1st to 10th	Day	47% 5% 14% 26% 8%	4500
	11th to 20th	Day	52% 8% 14% 20% 6%	4755
	21st to end	Day	60% 7% 11% 16% 6%	5780
April	1st to 10th	Day	43% 7% 13% 23% 13% 2	2400
	11th to 20th	Day	53% 6% 11% 19% 10% 1	2371
	21st to end	Day	48% 6% 14% 23% 9%	2470
May	1st to 10th	Day	45% 8% 14% 22% 10% 1	4275
	11th to 20th	Day	42% 6% 13% 26% 11% 1	4392
	21st to end	Day	42% 8% 12% 29% 9%	5079
June	1st to 10th	Day	37% 7% 18% 26% 11% 1	2850
	11th to 20th	Day	39% 9% 18% 23% 10% 1	2850
	21st to end	Day	34% 10% 19% 27% 10% 1	2850
July	1st to 10th	Day	29% 9% 23% 29% 8% 1	4654
	11th to 20th	Day	22% 6% 15% 40% 16% 2	4355
	21st to end	Day	24% 8% 19% 34% 15% 1	4651
August	1st to 10th	Day	32% 6% 15% 27% 17% 2	4396
	11th to 20th	Day	34% 7% 17% 33% 9%	4148
	21st to end	Day	27% 5% 16% 37% 14% 1	4384
September	1st to 10th	Day	29% 7% 12% 32% 18% 1	2280
	11th to 20th	Day	32% 6% 16% 28% 16% 1	2138
	21st to end	Day	35% 6% 13% 30% 15% 2	2090
October	1st to 10th	Day	31% 4 12% 29% 20% 4	3432
	11th to 20th	Day	31% 4 14% 38% 12%	2842
	21st to end	Day	43% 5% 10% 28% 14% 1	3091
November	1st to 10th	Day	48% 5% 13% 22% 10% 1	1763
	11th to 20th	Day	49% 5% 16% 20% 8% 1	1671
	21st to end	Day	50% 7% 17% 19% 7% 1	1400
December	1st to 10th	Day	55% 6% 19% 15% 5%	2290
	11th to 20th	Day	60% 6% 15% 15% 3	2640
	21st to end	Day	47% 4 11% 23% 14% 1	3498
January	1st to 10th	Night	59% 6% 12% 17% 6%	6450
	11th to 20th	Night	52% 6% 16% 17% 8%	6340
	21st to end	Night	50% 5% 18% 20% 6%	6974
February	1st to 10th	Night	56% 6% 11% 17% 10% 1	2800
	11th to 20th	Night	49% 6% 12% 20% 12% 1	2442
	21st to end	Night	42% 7% 15% 23% 11% 1	1980
March	1st to 10th	Night	45% 5% 14% 26% 10%	5374
	11th to 20th	Night	43% 8% 17% 24% 7%	5215
	21st to end	Night	53% 8% 14% 20% 6%	5162
April	1st to 10th	Night	39% 7% 12% 24% 16% 2	2000
	11th to 20th	Night	47% 7% 12% 21% 12% 2	1765
	21st to end	Night	42% 6% 14% 25% 12% 1	1710
May	1st to 10th	Night	41% 8% 14% 26% 10% 2	2680
	11th to 20th	Night	39% 8% 15% 24% 13% 1	2518
	21st to end	Night	38% 7% 16% 28% 10% 1	2492
June	1st to 10th	Night	32% 8% 17% 27% 13% 3	1330
	11th to 20th	Night	34% 8% 16% 26% 13% 2	1330
	21st to end	Night	28% 10% 19% 30% 11% 1	1330
July	1st to 10th	Night	25% 10% 22% 32% 9% 1	2203
	11th to 20th	Night	25% 7% 14% 38% 15% 2	2492
	21st to end	Night	22% 7% 20% 31% 17% 3	2674
August	1st to 10th	Night	27% 6% 14% 34% 17% 3	2520
	11th to 20th	Night	29% 7% 17% 33% 13% 1	2757
	21st to end	Night	23% 5% 13% 41% 17% 2	3280
September	1st to 10th	Night	25% 6% 11% 32% 24% 3	1900
	11th to 20th	Night	31% 6% 17% 26% 17% 2	2042
	21st to end	Night	36% 4 10% 31% 17% 2	2090
October	1st to 10th	Night	30% 4 9% 31% 21% 5%	3527
	11th to 20th	Night	34% 4 10% 35% 16% 1	4054
	21st to end	Night	37% 5% 11% 34% 12% 1	4467
November	1st to 10th	Night	44% 7% 13% 22% 13% 2	2535
	11th to 20th	Night	49% 7% 14% 22% 7% 1	2725
	21st to end	Night	47% 7% 17% 21% 8% 1	3000
December	1st to 10th	Night	55% 6% 20% 15% 4	4900
	11th to 20th	Night	57% 5% 19% 14% 4 1	5566
	21st to end	Night	50% 5% 11% 20% 13% 1	7480

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	9% 9% 36% 30% 13% 4	300
	11th to 20th	Day	8% 14% 39% 32% 6% 1	300
	21st to end	Day	12% 12% 36% 27% 11% 2	330
February	1st to 10th	Day	11% 11% 43% 31% 5%	300
	11th to 20th	Day	9% 10% 42% 27% 11% 2	300
	21st to end	Day	8% 12% 36% 34% 10%	249
March	1st to 10th	Day	14% 11% 37% 26% 10% 2	300
	11th to 20th	Day	12% 10% 32% 30% 14% 1	300
	21st to end	Day	16% 11% 34% 28% 9% 2	465
April	1st to 10th	Day	14% 16% 39% 25% 6% 1	500
	11th to 20th	Day	22% 15% 31% 23% 8% 1	569
	21st to end	Day	20% 9% 30% 28% 13% 1	650
May	1st to 10th	Day	15% 11% 27% 32% 13% 2	653
	11th to 20th	Day	18% 10% 26% 29% 12% 5%	675
	21st to end	Day	18% 10% 25% 27% 15% 5%	734
June	1st to 10th	Day	12% 10% 31% 27% 17% 4	680
	11th to 20th	Day	11% 12% 37% 25% 13% 2	680
	21st to end	Day	10% 10% 30% 35% 13% 3	680
July	1st to 10th	Day	8% 4 26% 38% 19% 5%	671
	11th to 20th	Day	7% 6% 29% 34% 18% 5%	668
	21st to end	Day	5% 4 30% 34% 23% 5%	739
August	1st to 10th	Day	9% 6% 26% 33% 21% 5%	676
	11th to 20th	Day	10% 3 23% 35% 24% 6%	665
	21st to end	Day	8% 9% 27% 32% 19% 5%	666
September	1st to 10th	Day	10% 10% 31% 29% 16% 4	490
	11th to 20th	Day	14% 8% 29% 32% 16% 1	348
	21st to end	Day	17% 12% 34% 25% 10% 2	300
October	1st to 10th	Day	22% 10% 28% 25% 12% 4	300
	11th to 20th	Day	12% 17% 31% 26% 11% 2	300
	21st to end	Day	18% 13% 40% 22% 5% 2	330
November	1st to 10th	Day	21% 11% 34% 21% 12%	300
	11th to 20th	Day	15% 13% 35% 31% 6%	300
	21st to end	Day	12% 13% 35% 28% 11% 1	300
December	1st to 10th	Day	10% 13% 46% 20% 10% 2	300
	11th to 20th	Day	16% 15% 40% 23% 5% 1	300
	21st to end	Day	12% 10% 39% 26% 11% 3	330
January	1st to 10th	Night	10% 11% 42% 28% 8% 1	1000
	11th to 20th	Night	12% 13% 40% 29% 7% 1	1000
	21st to end	Night	11% 11% 40% 29% 9%	1100
February	1st to 10th	Night	12% 12% 37% 30% 8% 1	1000
	11th to 20th	Night	11% 8% 39% 30% 10% 2	849
	21st to end	Night	11% 7% 37% 33% 10% 2	660
March	1st to 10th	Night	13% 10% 35% 31% 9% 2	800
	11th to 20th	Night	10% 10% 37% 31% 10% 1	705
	21st to end	Night	15% 7% 36% 30% 11% 2	660
April	1st to 10th	Night	11% 10% 39% 34% 7%	600
	11th to 20th	Night	16% 11% 35% 31% 7% 1	565
	21st to end	Night	18% 8% 31% 34% 10% 1	570
May	1st to 10th	Night	14% 5% 30% 36% 15%	570
	11th to 20th	Night	15% 7% 29% 38% 11%	561
	21st to end	Night	17% 6% 28% 35% 12%	617
June	1st to 10th	Night	13% 6% 34% 32% 15%	570
	11th to 20th	Night	13% 7% 36% 34% 11%	570
	21st to end	Night	8% 5% 31% 42% 15%	570
July	1st to 10th	Night	6% 4 25% 43% 22% 1	555
	11th to 20th	Night	6% 3 31% 44% 15% 1	552
	21st to end	Night	5% 2 27% 47% 17% 2	624
August	1st to 10th	Night	8% 3 23% 48% 17% 1	567
	11th to 20th	Night	7% 3 28% 43% 18% 1	564
	21st to end	Night	6% 4 31% 43% 15% 1	627
September	1st to 10th	Night	10% 4 31% 36% 17% 2	570
	11th to 20th	Night	11% 4 35% 39% 10% 1	570
	21st to end	Night	15% 7% 34% 32% 11% 1	570
October	1st to 10th	Night	14% 8% 35% 31% 11%	591
	11th to 20th	Night	15% 12% 30% 33% 9% 1	920
	21st to end	Night	15% 11% 38% 28% 8% 1	1045
November	1st to 10th	Night	16% 12% 35% 29% 8% 1	975
	11th to 20th	Night	13% 12% 38% 26% 9% 1	1000
	21st to end	Night	14% 14% 39% 26% 7% 1	1000
December	1st to 10th	Night	12% 9% 43% 29% 6% 1	1000
	11th to 20th	Night	15% 13% 36% 28% 8% 1	1000
	21st to end	Night	18% 7% 35% 30% 9% 1	1100

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