Fargo
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fargo clear sky chart from 2005-11-06 to 2025-10-19.

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	11% 8% 3 8% 5% 5% 5% 4 6% 7% 39%	135673
	Night	10% 9% 3 9% 5% 5% 5% 4 6% 7% 37%	131380
Transparency	Day	44% 6% 15% 25% 9% 1	130326
	Night	46% 6% 14% 23% 10% 1	127734
Seeing	Day	15% 9% 31% 29% 13% 3	17464
	Night	14% 8% 33% 33% 10% 1	27292

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	6% 11% 6% 14% 11% 9% 8% 5% 8% 6% 16%	3178
	11th to 20th	Day	5% 8% 4 12% 8% 9% 13% 7% 9% 7% 18%	3479
	21st to end	Day	5% 12% 8% 16% 8% 6% 4 4 5% 6% 25%	4153
February	1st to 10th	Day	8% 14% 6% 9% 7% 6% 7% 5% 6% 6% 25%	1800
	11th to 20th	Day	6% 11% 5% 10% 7% 8% 7% 5% 7% 8% 25%	1754
	21st to end	Day	9% 12% 4 12% 7% 7% 5% 5% 8% 8% 23%	1600
March	1st to 10th	Day	10% 9% 3 8% 5% 5% 5% 3 5% 8% 40%	4693
	11th to 20th	Day	10% 9% 4 9% 6% 5% 5% 5% 6% 9% 32%	4980
	21st to end	Day	17% 14% 5% 11% 6% 4 4 4 5% 6% 26%	5464
April	1st to 10th	Day	15% 11% 3 8% 6% 4 4 3 5% 6% 35%	2358
	11th to 20th	Day	17% 11% 4 8% 4 4 5% 3 5% 6% 33%	2569
	21st to end	Day	22% 9% 4 7% 4 4 4 4 6% 5% 32%	2600
May	1st to 10th	Day	13% 5% 2 5% 4 3 4 3 4 7% 50%	5900
	11th to 20th	Day	16% 8% 2 6% 4 4 4 4 5% 7% 41%	6268
	21st to end	Day	15% 6% 2 6% 4 4 4 4 6% 7% 42%	7314
June	1st to 10th	Day	13% 5% 2 6% 4 4 5% 4 7% 9% 42%	3000
	11th to 20th	Day	15% 5% 2 5% 5% 4 4 4 7% 7% 41%	3000
	21st to end	Day	11% 5% 2 5% 4 4 5% 4 7% 9% 42%	3000
July	1st to 10th	Day	6% 4 2 6% 4 5% 5% 4 7% 10% 48%	6799
	11th to 20th	Day	9% 5% 2 6% 3 4 4 3 6% 9% 50%	6800
	21st to end	Day	8% 5% 2 6% 4 4 5% 5% 7% 10% 45%	6895
August	1st to 10th	Day	13% 4 2 6% 4 4 4 4 7% 9% 43%	5801
	11th to 20th	Day	14% 6% 2 6% 4 3 4 4 5% 8% 44%	5821
	21st to end	Day	7% 4 1 5% 3 4 4 4 5% 8% 55%	6490
September	1st to 10th	Day	11% 4 2 5% 4 3 4 3 5% 8% 51%	2419
	11th to 20th	Day	12% 5% 2 6% 4 4 4 4 5% 8% 46%	2200
	21st to end	Day	13% 5% 2 6% 4 3 4 3 6% 7% 47%	2200
October	1st to 10th	Day	11% 5% 2 5% 3 4 3 3 5% 7% 54%	3326
	11th to 20th	Day	14% 8% 3 6% 4 3 3 3 3 6% 48%	3220
	21st to end	Day	16% 9% 3 8% 4 5% 5% 3 6% 7% 35%	3160
November	1st to 10th	Day	14% 12% 5% 11% 4 5% 4 3 4 5% 34%	1673
	11th to 20th	Day	11% 15% 5% 12% 8% 5% 4 2 5% 5% 29%	1600
	21st to end	Day	10% 13% 6% 12% 8% 4 4 3 4 5% 32%	1600
December	1st to 10th	Day	8% 13% 5% 15% 12% 8% 5% 5% 5% 5% 19%	2418
	11th to 20th	Day	9% 17% 7% 11% 6% 6% 6% 5% 6% 6% 23%	2643
	21st to end	Day	16% 14% 4 17% 8% 6% 4 3 3 4 21%	3498
January	1st to 10th	Night	5% 10% 5% 16% 11% 10% 9% 5% 6% 7% 17%	6787
	11th to 20th	Night	4 11% 4 11% 9% 9% 12% 9% 8% 6% 16%	6498
	21st to end	Night	6% 13% 8% 12% 6% 6% 6% 4 6% 6% 28%	6825
February	1st to 10th	Night	8% 11% 5% 10% 6% 6% 6% 5% 6% 6% 31%	2600
	11th to 20th	Night	6% 10% 4 10% 7% 7% 6% 6% 6% 6% 31%	2533
	21st to end	Night	9% 11% 4 10% 5% 6% 6% 5% 5% 6% 33%	2045
March	1st to 10th	Night	7% 8% 3 7% 5% 4 4 4 6% 9% 44%	5172
	11th to 20th	Night	9% 10% 4 11% 6% 5% 5% 4 6% 6% 35%	4980
	21st to end	Night	16% 14% 5% 9% 4 4 4 3 4 6% 32%	5467
April	1st to 10th	Night	13% 8% 3 7% 4 4 4 4 5% 8% 40%	2038
	11th to 20th	Night	18% 10% 3 6% 4 4 4 4 5% 5% 37%	1779
	21st to end	Night	19% 9% 3 6% 5% 3 3 3 5% 6% 37%	1800
May	1st to 10th	Night	13% 7% 2 5% 4 2 4 3 5% 6% 50%	4080
	11th to 20th	Night	16% 7% 2 4 3 4 4 3 6% 7% 44%	3646
	21st to end	Night	13% 6% 2 7% 4 4 5% 4 5% 6% 45%	3566
June	1st to 10th	Night	10% 3 2 4 5% 4 3 4 7% 10% 47%	1400
	11th to 20th	Night	10% 5% 2 5% 3 5% 4 4 7% 8% 47%	1400
	21st to end	Night	7% 4 2 5% 4 4 5% 4 7% 10% 50%	1400
July	1st to 10th	Night	8% 4 2 4 4 4 5% 4 7% 9% 49%	3180
	11th to 20th	Night	5% 3 1 4 3 3 3 4 6% 9% 58%	3180
	21st to end	Night	7% 5% 2 6% 4 4 5% 4 7% 10% 45%	3975
August	1st to 10th	Night	12% 5% 1 5% 3 4 4 4 6% 7% 49%	4011
	11th to 20th	Night	13% 5% 2 5% 3 3 4 3 5% 9% 48%	4028
	21st to end	Night	7% 4 1 5% 3 3 3 4 5% 7% 56%	4487
September	1st to 10th	Night	9% 3 1 4 3 4 4 2 6% 8% 56%	1977
	11th to 20th	Night	9% 5% 2 5% 4 4 5% 3 4 7% 53%	2200
	21st to end	Night	12% 4 1 5% 3 3 3 3 5% 7% 54%	2200
October	1st to 10th	Night	8% 4 2 4 3 3 3 3 4 6% 59%	3820
	11th to 20th	Night	13% 7% 2 5% 4 4 4 3 5% 7% 46%	3876
	21st to end	Night	15% 9% 3 7% 4 4 4 3 5% 6% 40%	4395
November	1st to 10th	Night	11% 11% 4 9% 4 4 5% 4 6% 7% 34%	2624
	11th to 20th	Night	11% 13% 5% 11% 5% 5% 5% 3 5% 6% 31%	2800
	21st to end	Night	11% 10% 3 9% 7% 5% 5% 3 6% 6% 35%	2800
December	1st to 10th	Night	5% 11% 5% 17% 10% 8% 5% 4 5% 6% 24%	4767
	11th to 20th	Night	10% 14% 5% 14% 8% 6% 5% 4 5% 5% 24%	5564
	21st to end	Night	15% 16% 5% 15% 9% 6% 5% 3 4 4 19%	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	66% 5% 10% 14% 5%	3179
	11th to 20th	Day	61% 6% 12% 16% 4	3479
	21st to end	Day	60% 5% 14% 16% 5%	4153
February	1st to 10th	Day	58% 6% 12% 17% 7%	1800
	11th to 20th	Day	54% 6% 14% 19% 6% 1	1763
	21st to end	Day	56% 8% 15% 16% 6%	1600
March	1st to 10th	Day	43% 5% 17% 26% 8% 1	4693
	11th to 20th	Day	48% 5% 17% 25% 5%	4980
	21st to end	Day	60% 5% 13% 18% 4	5464
April	1st to 10th	Day	50% 5% 11% 22% 10% 1	2358
	11th to 20th	Day	52% 6% 13% 18% 11% 1	2572
	21st to end	Day	51% 6% 12% 22% 8% 1	2600
May	1st to 10th	Day	34% 5% 14% 30% 16% 1	5900
	11th to 20th	Day	42% 6% 11% 21% 16% 4	6272
	21st to end	Day	39% 6% 11% 30% 13% 1	7315
June	1st to 10th	Day	38% 7% 17% 28% 10% 1	3000
	11th to 20th	Day	40% 7% 17% 24% 12% 1	3000
	21st to end	Day	35% 8% 18% 26% 12%	3000
July	1st to 10th	Day	31% 6% 22% 30% 10%	6726
	11th to 20th	Day	31% 5% 17% 36% 10% 1	6719
	21st to end	Day	34% 6% 20% 31% 9% 1	6695
August	1st to 10th	Day	32% 6% 16% 31% 13% 1	4220
	11th to 20th	Day	38% 5% 17% 31% 9% 1	4210
	21st to end	Day	32% 5% 20% 33% 10% 1	4674
September	1st to 10th	Day	32% 6% 15% 35% 11% 1	2419
	11th to 20th	Day	37% 7% 18% 28% 10%	2200
	21st to end	Day	35% 7% 14% 32% 10% 1	2200
October	1st to 10th	Day	31% 4 10% 37% 17% 1	3326
	11th to 20th	Day	40% 4 9% 30% 16%	3220
	21st to end	Day	51% 4 15% 23% 8%	3160
November	1st to 10th	Day	53% 5% 14% 17% 10% 1	1673
	11th to 20th	Day	59% 6% 13% 16% 7%	1600
	21st to end	Day	56% 7% 15% 17% 5% 1	1600
December	1st to 10th	Day	67% 6% 13% 12% 2	2418
	11th to 20th	Day	61% 6% 15% 14% 4	2640
	21st to end	Day	69% 4 10% 14% 3	3498
January	1st to 10th	Night	65% 6% 10% 15% 4	6787
	11th to 20th	Night	62% 8% 11% 13% 6%	6498
	21st to end	Night	57% 6% 16% 18% 3	6825
February	1st to 10th	Night	51% 7% 15% 18% 8% 1	2600
	11th to 20th	Night	50% 6% 12% 21% 11%	2534
	21st to end	Night	51% 6% 13% 21% 9% 1	2045
March	1st to 10th	Night	37% 5% 19% 26% 11% 1	5172
	11th to 20th	Night	49% 5% 13% 23% 9%	4980
	21st to end	Night	55% 5% 13% 20% 7%	5467
April	1st to 10th	Night	42% 6% 14% 23% 13% 2	2038
	11th to 20th	Night	47% 5% 9% 23% 13% 2	1779
	21st to end	Night	48% 6% 10% 24% 11% 2	1800
May	1st to 10th	Night	35% 6% 15% 22% 21% 1	4080
	11th to 20th	Night	38% 7% 9% 23% 18% 6%	3647
	21st to end	Night	39% 5% 10% 27% 17% 1	3567
June	1st to 10th	Night	30% 7% 17% 33% 11% 2	1400
	11th to 20th	Night	34% 7% 16% 25% 14% 5%	1400
	21st to end	Night	28% 9% 19% 30% 12% 2	1400
July	1st to 10th	Night	31% 7% 18% 32% 12% 1	3145
	11th to 20th	Night	22% 6% 19% 41% 11% 1	3138
	21st to end	Night	34% 5% 22% 29% 10% 1	3862
August	1st to 10th	Night	29% 6% 14% 32% 17% 2	2916
	11th to 20th	Night	32% 5% 16% 35% 12% 1	2915
	21st to end	Night	32% 6% 15% 32% 15% 1	3234
September	1st to 10th	Night	26% 6% 15% 37% 15% 1	1977
	11th to 20th	Night	31% 6% 17% 31% 14%	2200
	21st to end	Night	31% 5% 13% 32% 17% 1	2200
October	1st to 10th	Night	27% 4 9% 36% 19% 5%	3820
	11th to 20th	Night	39% 4 10% 28% 18% 2	3876
	21st to end	Night	46% 5% 12% 25% 12%	4395
November	1st to 10th	Night	48% 6% 12% 22% 11% 2	2624
	11th to 20th	Night	55% 7% 13% 17% 9% 1	2800
	21st to end	Night	50% 7% 18% 19% 7%	2800
December	1st to 10th	Night	61% 6% 17% 13% 3	4767
	11th to 20th	Night	62% 5% 13% 16% 3	5566
	21st to end	Night	70% 4 11% 12% 3	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	10% 10% 35% 33% 10% 2	300
	11th to 20th	Day	13% 8% 39% 32% 8%	300
	21st to end	Day	18% 11% 32% 29% 8% 2	330
February	1st to 10th	Day	16% 16% 32% 30% 5%	300
	11th to 20th	Day	11% 12% 46% 23% 7% 1	300
	21st to end	Day	11% 7% 41% 35% 6%	249
March	1st to 10th	Day	13% 15% 37% 28% 7%	300
	11th to 20th	Day	18% 9% 36% 25% 9% 4	300
	21st to end	Day	19% 11% 28% 30% 11% 2	330
April	1st to 10th	Day	23% 14% 31% 23% 8%	458
	11th to 20th	Day	25% 14% 27% 27% 7% 1	690
	21st to end	Day	23% 11% 32% 23% 10% 2	700
May	1st to 10th	Day	19% 10% 30% 26% 13% 1	703
	11th to 20th	Day	18% 9% 29% 29% 12% 3	725
	21st to end	Day	17% 8% 26% 30% 15% 4	789
June	1st to 10th	Day	11% 9% 28% 31% 18% 3	730
	11th to 20th	Day	15% 8% 39% 23% 13% 2	730
	21st to end	Day	12% 8% 30% 32% 14% 4	730
July	1st to 10th	Day	7% 3 25% 34% 24% 6%	721
	11th to 20th	Day	9% 5% 30% 33% 19% 4	718
	21st to end	Day	5% 4 29% 36% 21% 6%	794
August	1st to 10th	Day	9% 4 24% 36% 24% 3	726
	11th to 20th	Day	13% 5% 22% 32% 20% 9%	715
	21st to end	Day	9% 6% 28% 33% 21% 3	803
September	1st to 10th	Day	9% 6% 33% 30% 18% 4	549
	11th to 20th	Day	14% 8% 35% 31% 10% 2	330
	21st to end	Day	15% 13% 31% 25% 12% 4	330
October	1st to 10th	Day	17% 9% 31% 30% 11% 2	330
	11th to 20th	Day	19% 17% 32% 24% 7%	324
	21st to end	Day	22% 16% 34% 20% 7% 1	330
November	1st to 10th	Day	21% 10% 30% 31% 8% 1	300
	11th to 20th	Day	18% 14% 39% 22% 6% 1	300
	21st to end	Day	16% 16% 37% 28% 4	300
December	1st to 10th	Day	14% 7% 37% 32% 9% 1	300
	11th to 20th	Day	18% 11% 41% 26% 3	300
	21st to end	Day	20% 12% 34% 25% 8% 1	330
January	1st to 10th	Night	10% 8% 39% 32% 9% 2	1000
	11th to 20th	Night	14% 10% 36% 34% 7%	1000
	21st to end	Night	14% 8% 40% 30% 8% 1	1100
February	1st to 10th	Night	12% 10% 33% 35% 8% 1	1000
	11th to 20th	Night	12% 10% 39% 30% 8% 2	979
	21st to end	Night	14% 9% 33% 30% 13% 1	725
March	1st to 10th	Night	15% 10% 36% 31% 9% 1	715
	11th to 20th	Night	14% 10% 39% 29% 8% 1	600
	21st to end	Night	17% 8% 31% 30% 11% 2	660
April	1st to 10th	Night	17% 11% 34% 32% 7%	600
	11th to 20th	Night	23% 10% 32% 26% 8% 1	593
	21st to end	Night	22% 10% 32% 26% 10%	600
May	1st to 10th	Night	18% 8% 32% 33% 9% 1	600
	11th to 20th	Night	16% 7% 34% 32% 11%	591
	21st to end	Night	13% 8% 34% 33% 11% 1	650
June	1st to 10th	Night	10% 7% 30% 41% 12%	600
	11th to 20th	Night	13% 5% 34% 40% 8%	600
	21st to end	Night	8% 5% 27% 47% 13% 1	600
July	1st to 10th	Night	6% 2 23% 46% 21% 2	585
	11th to 20th	Night	6% 3 27% 47% 16% 1	582
	21st to end	Night	5% 3 24% 46% 20% 2	657
August	1st to 10th	Night	8% 3 21% 50% 17% 2	597
	11th to 20th	Night	10% 5% 22% 40% 21% 2	594
	21st to end	Night	9% 4 31% 38% 18% 1	660
September	1st to 10th	Night	9% 5% 30% 39% 15% 2	600
	11th to 20th	Night	10% 6% 30% 41% 13% 1	600
	21st to end	Night	14% 6% 33% 36% 12%	600
October	1st to 10th	Night	17% 9% 33% 31% 9%	739
	11th to 20th	Night	21% 10% 32% 29% 8%	793
	21st to end	Night	23% 10% 35% 26% 5%	997
November	1st to 10th	Night	17% 9% 33% 33% 7%	975
	11th to 20th	Night	17% 11% 36% 27% 8% 1	1000
	21st to end	Night	16% 11% 40% 28% 5%	1000
December	1st to 10th	Night	13% 9% 38% 31% 8% 1	1000
	11th to 20th	Night	18% 9% 39% 28% 6% 1	1000
	21st to end	Night	23% 8% 36% 26% 6% 1	1100

Page generated at 2025-10-16 00:50:24. Version ac07

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