Big Bend City(MN)
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Big Bend City(MN) clear sky chart from 2005-11-06 to 2025-10-04.

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	12% 8% 3 7% 5% 5% 5% 4 6% 7% 39%	126710
	Night	10% 9% 3 8% 5% 5% 5% 4 5% 7% 39%	122937
Transparency	Day	42% 5% 14% 26% 12% 1	130254
	Night	43% 5% 13% 25% 12% 2	127460
Seeing	Day	16% 8% 29% 29% 15% 3	17331
	Night	15% 7% 31% 35% 11% 1	27133

By Month

Percentage Cloud Cover SE (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	8% 13% 4 12% 12% 9% 8% 4 5% 6% 18%	3178
	11th to 20th	Day	6% 9% 5% 11% 6% 9% 9% 8% 11% 8% 18%	3666
	21st to end	Day	5% 11% 10% 12% 7% 6% 5% 4 5% 6% 29%	4488
February	1st to 10th	Day	8% 13% 6% 9% 7% 5% 7% 6% 6% 8% 26%	1800
	11th to 20th	Day	7% 12% 4 10% 8% 7% 7% 6% 5% 7% 28%	1754
	21st to end	Day	9% 12% 5% 11% 8% 6% 5% 4 6% 8% 28%	1580
March	1st to 10th	Day	11% 9% 3 7% 5% 4 4 3 5% 7% 42%	4821
	11th to 20th	Day	10% 9% 3 7% 5% 4 5% 4 6% 8% 41%	4980
	21st to end	Day	22% 13% 4 11% 6% 6% 4 4 5% 6% 20%	5462
April	1st to 10th	Day	17% 10% 3 6% 4 3 4 3 6% 7% 37%	2315
	11th to 20th	Day	19% 11% 4 8% 4 4 4 3 4 6% 33%	2549
	21st to end	Day	22% 9% 2 7% 4 5% 4 3 5% 6% 34%	2600
May	1st to 10th	Day	12% 5% 2 5% 4 4 4 3 5% 7% 50%	5862
	11th to 20th	Day	19% 8% 2 5% 3 3 4 3 5% 6% 43%	6223
	21st to end	Day	15% 7% 2 7% 4 4 5% 4 7% 8% 36%	6935
June	1st to 10th	Day	12% 5% 2 5% 5% 4 4 4 6% 8% 46%	2955
	11th to 20th	Day	15% 7% 2 6% 5% 5% 4 5% 5% 7% 39%	3000
	21st to end	Day	9% 5% 2 5% 4 4 4 4 7% 9% 47%	3000
July	1st to 10th	Day	7% 4 2 5% 4 4 6% 5% 7% 10% 46%	6800
	11th to 20th	Day	7% 4 2 4 3 3 4 3 5% 8% 57%	6784
	21st to end	Day	7% 4 2 6% 4 4 5% 4 7% 11% 46%	6430
August	1st to 10th	Day	12% 5% 2 5% 4 4 4 4 6% 9% 45%	4234
	11th to 20th	Day	12% 5% 2 6% 4 4 5% 4 6% 9% 42%	4171
	21st to end	Day	8% 4 2 6% 4 4 4 4 6% 7% 51%	4657
September	1st to 10th	Day	11% 4 2 5% 3 4 4 3 5% 7% 53%	2400
	11th to 20th	Day	10% 5% 2 5% 4 4 4 5% 6% 8% 46%	2202
	21st to end	Day	14% 5% 2 4 3 3 3 3 5% 6% 52%	2200
October	1st to 10th	Day	15% 7% 2 6% 4 3 4 3 5% 6% 45%	1940
	11th to 20th	Day	15% 9% 2 6% 3 3 4 3 5% 6% 44%	1900
	21st to end	Day	17% 9% 3 6% 4 3 4 3 6% 6% 40%	2022
November	1st to 10th	Day	13% 10% 3 9% 4 4 3 3 5% 7% 40%	1678
	11th to 20th	Day	9% 12% 5% 12% 8% 5% 5% 4 5% 7% 31%	1600
	21st to end	Day	12% 10% 4 10% 6% 4 4 4 5% 7% 34%	1600
December	1st to 10th	Day	6% 10% 5% 12% 10% 9% 6% 4 6% 8% 25%	2610
	11th to 20th	Day	9% 18% 7% 12% 7% 6% 5% 3 5% 6% 22%	2816
	21st to end	Day	17% 15% 4 21% 5% 4 3 3 4 5% 17%	3498
January	1st to 10th	Night	6% 10% 5% 16% 12% 9% 7% 5% 5% 6% 20%	6787
	11th to 20th	Night	5% 8% 4 13% 9% 8% 12% 7% 8% 6% 21%	6309
	21st to end	Night	5% 14% 8% 9% 5% 4 5% 4 6% 6% 34%	6490
February	1st to 10th	Night	6% 11% 5% 11% 7% 6% 6% 4 5% 7% 32%	2600
	11th to 20th	Night	6% 9% 4 10% 6% 6% 6% 5% 6% 7% 36%	2533
	21st to end	Night	10% 10% 4 7% 7% 5% 5% 5% 6% 6% 35%	2068
March	1st to 10th	Night	10% 6% 2 5% 4 4 4 3 5% 8% 48%	5037
	11th to 20th	Night	9% 7% 2 6% 4 4 4 4 6% 9% 42%	4980
	21st to end	Night	20% 12% 3 9% 5% 4 4 3 4 6% 30%	5467
April	1st to 10th	Night	14% 10% 3 5% 5% 3 4 3 6% 7% 39%	2084
	11th to 20th	Night	16% 10% 4 7% 4 5% 4 3 4 5% 37%	1799
	21st to end	Night	19% 9% 3 7% 4 4 5% 4 4 6% 37%	1800
May	1st to 10th	Night	12% 4 2 4 3 3 3 2 4 6% 57%	4053
	11th to 20th	Night	14% 8% 2 5% 3 3 3 3 4 6% 46%	3689
	21st to end	Night	18% 8% 3 6% 4 4 4 4 5% 7% 39%	3942
June	1st to 10th	Night	9% 5% 3 5% 4 3 4 4 6% 8% 51%	1440
	11th to 20th	Night	10% 5% 2 4 3 4 4 4 6% 7% 51%	1400
	21st to end	Night	9% 4 2 4 4 4 3 3 5% 7% 57%	1400
July	1st to 10th	Night	8% 4 2 5% 4 3 4 4 7% 10% 48%	3178
	11th to 20th	Night	6% 3 1 3 3 3 4 4 6% 8% 59%	3177
	21st to end	Night	8% 5% 2 6% 4 4 5% 4 6% 9% 46%	4438
August	1st to 10th	Night	9% 7% 2 6% 3 3 4 3 5% 7% 49%	2926
	11th to 20th	Night	12% 4 2 4 3 3 4 3 5% 6% 52%	2888
	21st to end	Night	7% 5% 1 6% 3 2 4 3 5% 8% 55%	3251
September	1st to 10th	Night	9% 4 2 4 2 3 4 3 5% 8% 58%	2000
	11th to 20th	Night	9% 5% 2 4 3 4 4 3 6% 6% 54%	2195
	21st to end	Night	10% 5% 2 5% 3 3 2 2 5% 5% 57%	2200
October	1st to 10th	Night	14% 6% 2 6% 4 3 3 3 4 6% 49%	2287
	11th to 20th	Night	14% 8% 2 4 4 4 4 3 5% 7% 46%	2280
	21st to end	Night	15% 9% 3 7% 4 3 4 3 5% 7% 40%	2574
November	1st to 10th	Night	10% 9% 3 7% 4 4 4 4 6% 8% 42%	2619
	11th to 20th	Night	10% 10% 4 9% 6% 5% 4 4 4 6% 38%	2800
	21st to end	Night	10% 10% 4 8% 5% 4 4 4 6% 7% 38%	2800
December	1st to 10th	Night	5% 9% 4 12% 8% 8% 5% 5% 6% 7% 31%	4580
	11th to 20th	Night	11% 12% 5% 12% 8% 6% 6% 4 6% 7% 25%	5386
	21st to end	Night	16% 16% 6% 16% 7% 5% 5% 4 4 4 18%	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% 4 12% 13% 5%	3179
	11th to 20th	Day	55% 5% 15% 17% 7%	3666
	21st to end	Day	53% 7% 15% 16% 8%	4488
February	1st to 10th	Day	55% 5% 13% 20% 7%	1800
	11th to 20th	Day	54% 5% 12% 20% 7% 1	1763
	21st to end	Day	53% 6% 14% 17% 9%	1580
March	1st to 10th	Day	41% 5% 15% 28% 10% 1	4821
	11th to 20th	Day	41% 4 13% 30% 10% 1	4980
	21st to end	Day	63% 6% 10% 17% 4	5464
April	1st to 10th	Day	46% 4 12% 25% 12% 1	2315
	11th to 20th	Day	52% 4 10% 20% 13% 1	2549
	21st to end	Day	51% 4 11% 24% 9% 1	2600
May	1st to 10th	Day	32% 5% 10% 30% 22% 1	5900
	11th to 20th	Day	42% 4 8% 21% 15% 9%	6227
	21st to end	Day	43% 7% 10% 29% 11% 1	6949
June	1st to 10th	Day	36% 5% 15% 30% 12% 2	2955
	11th to 20th	Day	42% 6% 13% 23% 14% 2	3000
	21st to end	Day	32% 6% 17% 29% 14% 2	3000
July	1st to 10th	Day	31% 8% 20% 29% 12%	6726
	11th to 20th	Day	26% 5% 15% 37% 15% 2	6703
	21st to end	Day	31% 7% 19% 30% 13% 1	6247
August	1st to 10th	Day	36% 5% 13% 31% 12% 2	4220
	11th to 20th	Day	37% 6% 16% 31% 8% 1	4210
	21st to end	Day	31% 6% 18% 29% 14% 2	4656
September	1st to 10th	Day	30% 5% 13% 38% 14% 1	2400
	11th to 20th	Day	34% 6% 17% 31% 11% 1	2202
	21st to end	Day	34% 4 12% 31% 18% 2	2200
October	1st to 10th	Day	30% 3 9% 30% 26% 1	3200
	11th to 20th	Day	35% 5% 12% 26% 21% 2	3140
	21st to end	Day	43% 4 16% 27% 10%	3315
November	1st to 10th	Day	44% 5% 13% 24% 12% 3	1678
	11th to 20th	Day	53% 5% 12% 21% 9% 1	1600
	21st to end	Day	49% 5% 16% 21% 7% 2	1600
December	1st to 10th	Day	56% 6% 15% 18% 5%	2610
	11th to 20th	Day	62% 6% 13% 14% 5%	2813
	21st to end	Day	68% 5% 10% 12% 5%	3498
January	1st to 10th	Night	63% 5% 10% 16% 6%	6787
	11th to 20th	Night	58% 6% 11% 15% 9% 1	6309
	21st to end	Night	49% 6% 16% 22% 8%	6490
February	1st to 10th	Night	51% 5% 14% 18% 10% 1	2600
	11th to 20th	Night	45% 6% 13% 23% 12% 1	2534
	21st to end	Night	48% 5% 12% 20% 12% 2	2068
March	1st to 10th	Night	34% 5% 12% 35% 13% 1	5037
	11th to 20th	Night	36% 5% 14% 32% 12%	4980
	21st to end	Night	56% 4 11% 21% 7% 1	5467
April	1st to 10th	Night	44% 4 12% 27% 11% 1	2084
	11th to 20th	Night	48% 4 7% 24% 14% 3	1799
	21st to end	Night	49% 5% 10% 22% 13% 2	1800
May	1st to 10th	Night	29% 4 11% 30% 23% 3	4080
	11th to 20th	Night	37% 6% 7% 19% 22% 8%	3690
	21st to end	Night	43% 6% 10% 28% 12% 1	3950
June	1st to 10th	Night	30% 5% 14% 31% 17% 3	1440
	11th to 20th	Night	31% 5% 18% 27% 16% 3	1400
	21st to end	Night	28% 4 16% 30% 19% 3	1400
July	1st to 10th	Night	29% 7% 18% 29% 16% 1	3145
	11th to 20th	Night	22% 5% 14% 44% 13% 2	3138
	21st to end	Night	32% 7% 18% 30% 12% 1	4310
August	1st to 10th	Night	35% 6% 14% 28% 15% 3	2916
	11th to 20th	Night	33% 5% 16% 32% 12% 1	2915
	21st to end	Night	28% 6% 17% 31% 16% 3	3251
September	1st to 10th	Night	27% 5% 14% 35% 19% 1	2000
	11th to 20th	Night	30% 4 16% 32% 17%	2195
	21st to end	Night	30% 4 11% 33% 21% 1	2200
October	1st to 10th	Night	24% 2 6% 34% 29% 4	3794
	11th to 20th	Night	31% 3 13% 30% 21% 2	3779
	21st to end	Night	40% 3 13% 29% 14% 1	4235
November	1st to 10th	Night	39% 5% 15% 24% 15% 2	2619
	11th to 20th	Night	48% 5% 13% 21% 13% 1	2800
	21st to end	Night	45% 4 18% 23% 9% 1	2800
December	1st to 10th	Night	50% 6% 19% 19% 6%	4580
	11th to 20th	Night	57% 6% 15% 18% 4	5388
	21st to end	Night	67% 6% 9% 14% 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	14% 8% 29% 30% 15% 4	300
	11th to 20th	Day	16% 10% 30% 33% 10% 1	300
	21st to end	Day	15% 8% 36% 25% 13% 2	330
February	1st to 10th	Day	14% 13% 38% 30% 5%	300
	11th to 20th	Day	15% 11% 36% 29% 8%	300
	21st to end	Day	15% 9% 36% 32% 7%	249
March	1st to 10th	Day	20% 7% 38% 28% 7%	300
	11th to 20th	Day	20% 7% 36% 27% 9% 1	300
	21st to end	Day	25% 8% 28% 25% 10% 3	330
April	1st to 10th	Day	28% 12% 30% 23% 6%	415
	11th to 20th	Day	26% 16% 26% 22% 9% 1	667
	21st to end	Day	25% 11% 32% 21% 10% 2	700
May	1st to 10th	Day	18% 11% 32% 26% 11% 2	703
	11th to 20th	Day	23% 8% 27% 25% 14% 3	725
	21st to end	Day	15% 7% 28% 32% 14% 3	789
June	1st to 10th	Day	11% 8% 25% 34% 20% 4	730
	11th to 20th	Day	17% 9% 33% 26% 12% 2	730
	21st to end	Day	11% 6% 32% 32% 16% 3	730
July	1st to 10th	Day	9% 3 23% 34% 26% 7%	721
	11th to 20th	Day	8% 6% 25% 36% 21% 5%	718
	21st to end	Day	6% 3 25% 38% 22% 5%	794
August	1st to 10th	Day	10% 3 20% 37% 25% 5%	726
	11th to 20th	Day	14% 4 18% 34% 22% 7%	715
	21st to end	Day	8% 4 27% 31% 24% 7%	798
September	1st to 10th	Day	12% 6% 27% 32% 18% 5%	530
	11th to 20th	Day	12% 3 32% 33% 16% 5%	332
	21st to end	Day	18% 10% 25% 26% 16% 5%	330
October	1st to 10th	Day	17% 8% 29% 27% 15% 4	309
	11th to 20th	Day	19% 14% 33% 23% 9% 2	300
	21st to end	Day	22% 13% 34% 22% 8% 1	330
November	1st to 10th	Day	25% 7% 26% 31% 10% 1	300
	11th to 20th	Day	17% 14% 38% 25% 5% 1	300
	21st to end	Day	21% 16% 32% 22% 10%	300
December	1st to 10th	Day	11% 7% 40% 29% 12% 1	300
	11th to 20th	Day	17% 9% 38% 27% 8%	300
	21st to end	Day	29% 8% 31% 23% 7% 1	330
January	1st to 10th	Night	11% 9% 35% 34% 10% 1	1000
	11th to 20th	Night	14% 10% 32% 35% 9% 1	1000
	21st to end	Night	17% 9% 33% 33% 8% 1	1100
February	1st to 10th	Night	12% 9% 38% 32% 8% 1	1000
	11th to 20th	Night	11% 10% 38% 31% 9% 1	979
	21st to end	Night	15% 10% 31% 32% 11% 1	748
March	1st to 10th	Night	16% 7% 36% 32% 9%	657
	11th to 20th	Night	17% 10% 36% 32% 5% 1	600
	21st to end	Night	20% 7% 31% 30% 10% 2	660
April	1st to 10th	Night	21% 9% 35% 28% 6%	600
	11th to 20th	Night	22% 12% 29% 28% 8% 1	593
	21st to end	Night	24% 5% 31% 31% 8% 1	600
May	1st to 10th	Night	18% 7% 32% 34% 9% 1	600
	11th to 20th	Night	19% 5% 32% 33% 11% 1	591
	21st to end	Night	17% 6% 28% 37% 12% 1	650
June	1st to 10th	Night	11% 6% 25% 41% 16% 1	600
	11th to 20th	Night	12% 4 34% 42% 9%	600
	21st to end	Night	11% 3 26% 47% 12% 1	600
July	1st to 10th	Night	6% 2 20% 46% 24% 2	585
	11th to 20th	Night	7% 2 26% 47% 18% 1	582
	21st to end	Night	6% 1 23% 49% 20% 2	657
August	1st to 10th	Night	9% 3 19% 47% 19% 2	597
	11th to 20th	Night	10% 3 16% 44% 23% 4	594
	21st to end	Night	5% 3 23% 46% 21% 2	660
September	1st to 10th	Night	10% 3 28% 39% 18% 2	600
	11th to 20th	Night	11% 4 30% 37% 17% 2	600
	21st to end	Night	13% 5% 31% 33% 17% 1	600
October	1st to 10th	Night	17% 8% 31% 31% 12% 1	743
	11th to 20th	Night	20% 8% 33% 29% 9%	760
	21st to end	Night	21% 9% 32% 31% 7%	902
November	1st to 10th	Night	16% 8% 33% 33% 10%	975
	11th to 20th	Night	16% 10% 37% 28% 9% 1	1000
	21st to end	Night	15% 12% 34% 30% 8%	1000
December	1st to 10th	Night	13% 8% 35% 34% 9% 1	1000
	11th to 20th	Night	20% 7% 30% 35% 7% 1	1000
	21st to end	Night	25% 8% 31% 28% 7% 1	1100

Page generated at 2025-10-01 00:39:03. Version ac07

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