Missouri Western State University
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Missouri Western State University clear sky chart from 2005-11-06 to 2025-03-27.

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% 7% 3 7% 4 4 4 3 5% 7% 44%	109111
	Night	11% 7% 3 7% 4 4 4 3 5% 6% 47%	110436
Transparency	Day	38% 5% 13% 26% 17% 2	112762
	Night	37% 4 12% 26% 19% 3	114925
Seeing	Day	14% 9% 29% 28% 15% 4	16148
	Night	14% 9% 32% 33% 11% 1	26193

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	14% 10% 3 10% 4 4 4 3 7% 8% 34%	4077
	11th to 20th	Day	7% 10% 3 9% 6% 6% 6% 3 4 5% 40%	4080
	21st to end	Day	11% 13% 5% 12% 5% 5% 4 2 5% 5% 33%	4488
February	1st to 10th	Day	13% 11% 4 9% 5% 5% 4 4 6% 6% 35%	1800
	11th to 20th	Day	11% 11% 4 7% 5% 4 4 3 6% 7% 40%	1754
	21st to end	Day	11% 10% 3 6% 4 3 3 4 5% 6% 46%	1676
March	1st to 10th	Day	14% 9% 2 6% 4 3 3 3 4 5% 46%	3546
	11th to 20th	Day	11% 7% 2 6% 3 3 4 3 5% 6% 49%	3590
	21st to end	Day	18% 12% 5% 7% 5% 3 4 3 5% 6% 31%	3880
April	1st to 10th	Day	14% 8% 2 7% 4 3 3 3 5% 7% 45%	2195
	11th to 20th	Day	15% 9% 3 6% 4 4 4 3 5% 7% 40%	2254
	21st to end	Day	21% 7% 2 7% 4 3 4 3 5% 7% 36%	2444
May	1st to 10th	Day	15% 8% 2 7% 4 4 4 4 5% 7% 40%	4082
	11th to 20th	Day	17% 7% 3 7% 4 4 4 3 5% 7% 39%	4082
	21st to end	Day	13% 6% 2 5% 4 3 4 3 5% 7% 46%	4685
June	1st to 10th	Day	6% 5% 1 5% 5% 5% 5% 5% 6% 9% 48%	2660
	11th to 20th	Day	8% 5% 2 5% 4 5% 5% 4 6% 9% 47%	2660
	21st to end	Day	8% 3 2 6% 4 5% 5% 4 7% 9% 48%	2660
July	1st to 10th	Day	11% 6% 2 6% 4 4 4 4 7% 9% 41%	4226
	11th to 20th	Day	7% 4 2 5% 4 3 4 3 6% 8% 54%	4120
	21st to end	Day	5% 3 2 5% 3 4 5% 5% 6% 10% 51%	4465
August	1st to 10th	Day	6% 4 2 5% 4 4 4 4 7% 9% 51%	4104
	11th to 20th	Day	11% 5% 2 6% 4 4 4 3 6% 9% 45%	4041
	21st to end	Day	6% 4 2 5% 4 4 5% 4 6% 8% 52%	4308
September	1st to 10th	Day	12% 3 1 4 3 3 4 3 6% 7% 53%	2280
	11th to 20th	Day	9% 5% 3 6% 4 5% 4 5% 5% 7% 49%	2107
	21st to end	Day	10% 4 2 4 3 4 4 2 4 6% 57%	2080
October	1st to 10th	Day	13% 5% 2 6% 3 3 3 2 5% 7% 52%	1900
	11th to 20th	Day	12% 5% 2 5% 2 3 3 2 4 5% 55%	1900
	21st to end	Day	14% 7% 3 6% 3 3 3 2 5% 7% 47%	2090
November	1st to 10th	Day	10% 6% 2 5% 4 4 3 3 4 8% 52%	1922
	11th to 20th	Day	13% 6% 2 5% 4 3 3 2 5% 7% 51%	1685
	21st to end	Day	15% 9% 3 6% 2 2 3 3 5% 7% 45%	1600
December	1st to 10th	Day	6% 5% 3 6% 4 4 4 3 5% 6% 54%	2610
	11th to 20th	Day	11% 7% 3 8% 4 4 4 3 4 6% 47%	3008
	21st to end	Day	18% 15% 7% 13% 5% 3 3 3 4 5% 24%	4052
January	1st to 10th	Night	11% 9% 4 16% 6% 5% 4 3 5% 6% 30%	5888
	11th to 20th	Night	8% 9% 3 9% 4 5% 5% 4 5% 5% 42%	5900
	21st to end	Night	13% 11% 4 12% 4 4 4 3 3 5% 38%	6490
February	1st to 10th	Night	11% 12% 4 9% 5% 4 4 4 4 5% 39%	2600
	11th to 20th	Night	11% 9% 3 8% 4 5% 4 3 5% 6% 42%	2533
	21st to end	Night	10% 8% 3 5% 4 3 3 4 5% 5% 48%	1967
March	1st to 10th	Night	12% 7% 2 6% 4 3 3 3 4 5% 51%	3529
	11th to 20th	Night	12% 6% 1 4 3 2 3 3 4 6% 55%	3590
	21st to end	Night	17% 10% 4 9% 4 4 4 3 5% 6% 33%	3889
April	1st to 10th	Night	10% 6% 2 6% 3 3 4 4 5% 7% 50%	1983
	11th to 20th	Night	13% 8% 3 6% 3 4 3 4 5% 5% 47%	1875
	21st to end	Night	15% 8% 3 6% 4 4 4 3 5% 7% 42%	1732
May	1st to 10th	Night	17% 6% 2 6% 4 4 4 4 5% 7% 43%	2823
	11th to 20th	Night	15% 7% 2 5% 4 4 4 3 4 7% 45%	2823
	21st to end	Night	13% 5% 2 5% 3 3 4 3 4 6% 51%	2878
June	1st to 10th	Night	5% 3 1 3 4 4 4 4 7% 8% 55%	1520
	11th to 20th	Night	5% 3 2 4 3 4 4 5% 7% 10% 53%	1520
	21st to end	Night	5% 2 1 4 3 3 4 3 5% 10% 60%	1520
July	1st to 10th	Night	11% 6% 3 5% 4 4 3 4 5% 9% 47%	2739
	11th to 20th	Night	3 3 1 4 3 3 4 3 6% 8% 62%	2850
	21st to end	Night	6% 3 2 4 3 4 4 5% 7% 11% 51%	3098
August	1st to 10th	Night	3 2 1 3 3 3 4 3 7% 10% 60%	2836
	11th to 20th	Night	12% 6% 2 5% 3 4 3 2 4 6% 53%	2798
	21st to end	Night	5% 4 2 5% 4 4 3 3 5% 7% 58%	3352
September	1st to 10th	Night	9% 4 1 5% 3 3 4 3 5% 6% 57%	1900
	11th to 20th	Night	8% 5% 1 4 4 3 4 4 5% 7% 54%	2069
	21st to end	Night	8% 4 1 5% 3 3 3 3 4 6% 60%	2090
October	1st to 10th	Night	12% 6% 2 4 3 3 3 2 5% 5% 57%	2270
	11th to 20th	Night	13% 4 2 4 3 3 3 2 4 5% 56%	2280
	21st to end	Night	15% 7% 2 5% 3 3 2 2 3 5% 52%	2508
November	1st to 10th	Night	9% 4 1 4 2 3 3 2 5% 7% 60%	2374
	11th to 20th	Night	11% 6% 2 5% 3 3 4 3 4 6% 53%	2711
	21st to end	Night	13% 8% 2 5% 3 3 4 2 4 5% 51%	2800
December	1st to 10th	Night	6% 6% 2 5% 3 3 4 3 5% 6% 56%	4580
	11th to 20th	Night	11% 8% 3 7% 4 4 3 3 5% 7% 45%	5199
	21st to end	Night	19% 17% 5% 9% 4 3 3 3 3 4 29%	6922

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	48% 4 13% 23% 10% 1	4078
	11th to 20th	Day	47% 3 12% 20% 14% 5%	4080
	21st to end	Day	54% 4 12% 16% 14% 1	4488
February	1st to 10th	Day	50% 4 12% 21% 11% 2	1800
	11th to 20th	Day	44% 5% 12% 23% 14% 2	1763
	21st to end	Day	38% 3 12% 25% 19% 3	1676
March	1st to 10th	Day	40% 4 11% 21% 22% 2	3546
	11th to 20th	Day	35% 4 11% 27% 21% 2	3590
	21st to end	Day	53% 5% 16% 20% 5% 1	3880
April	1st to 10th	Day	40% 5% 12% 25% 16% 2	2195
	11th to 20th	Day	44% 4 12% 23% 16% 1	2254
	21st to end	Day	48% 5% 11% 25% 11% 1	2444
May	1st to 10th	Day	44% 5% 11% 23% 14% 2	4120
	11th to 20th	Day	44% 5% 13% 24% 14%	4086
	21st to end	Day	37% 5% 11% 29% 15% 2	4698
June	1st to 10th	Day	31% 7% 15% 30% 15% 2	2660
	11th to 20th	Day	32% 7% 14% 29% 18% 1	2660
	21st to end	Day	30% 6% 16% 29% 15% 3	2660
July	1st to 10th	Day	37% 7% 15% 26% 12% 3	4162
	11th to 20th	Day	28% 6% 10% 34% 19% 3	4051
	21st to end	Day	25% 8% 16% 33% 15% 3	4325
August	1st to 10th	Day	28% 6% 16% 29% 20% 1	4090
	11th to 20th	Day	36% 6% 16% 26% 16% 1	4080
	21st to end	Day	28% 7% 16% 30% 14% 5%	4307
September	1st to 10th	Day	31% 5% 11% 26% 21% 5%	2280
	11th to 20th	Day	34% 5% 12% 26% 21% 2	2107
	21st to end	Day	30% 4 8% 32% 23% 3	2080
October	1st to 10th	Day	20% 2 7% 21% 45% 4	3160
	11th to 20th	Day	21% 3 5% 27% 36% 9%	3140
	21st to end	Day	32% 3 11% 27% 23% 3	3428
November	1st to 10th	Day	32% 3 12% 29% 19% 4	1922
	11th to 20th	Day	34% 3 11% 29% 20% 3	1685
	21st to end	Day	40% 3 12% 26% 18% 1	1600
December	1st to 10th	Day	30% 4 17% 31% 16% 1	2610
	11th to 20th	Day	40% 3 15% 31% 10% 1	3005
	21st to end	Day	64% 3 12% 14% 6% 1	4052
January	1st to 10th	Night	54% 5% 11% 20% 10% 1	5888
	11th to 20th	Night	43% 4 11% 23% 15% 4	5900
	21st to end	Night	51% 3 10% 16% 15% 4	6490
February	1st to 10th	Night	48% 4 11% 21% 13% 3	2600
	11th to 20th	Night	43% 4 12% 21% 16% 3	2534
	21st to end	Night	37% 4 9% 24% 20% 6%	1967
March	1st to 10th	Night	37% 3 11% 25% 21% 3	3529
	11th to 20th	Night	31% 4 8% 31% 21% 5%	3590
	21st to end	Night	50% 5% 16% 22% 6% 1	3889
April	1st to 10th	Night	33% 5% 11% 26% 20% 4	1983
	11th to 20th	Night	39% 4 11% 28% 15% 3	1875
	21st to end	Night	43% 4 10% 25% 17% 1	1732
May	1st to 10th	Night	40% 7% 12% 22% 18% 2	2850
	11th to 20th	Night	39% 6% 10% 28% 17%	2824
	21st to end	Night	34% 5% 12% 28% 20% 2	2886
June	1st to 10th	Night	24% 7% 18% 32% 16% 4	1520
	11th to 20th	Night	25% 6% 15% 30% 20% 3	1520
	21st to end	Night	20% 5% 16% 34% 20% 4	1520
July	1st to 10th	Night	35% 5% 12% 24% 20% 5%	2694
	11th to 20th	Night	19% 5% 15% 35% 23% 2	2796
	21st to end	Night	23% 8% 19% 33% 16% 1	2999
August	1st to 10th	Night	19% 6% 19% 27% 27% 2	2826
	11th to 20th	Night	34% 4 12% 28% 21% 1	2825
	21st to end	Night	26% 5% 14% 32% 18% 5%	3352
September	1st to 10th	Night	28% 5% 9% 27% 23% 8%	1900
	11th to 20th	Night	29% 4 9% 29% 25% 4	2069
	21st to end	Night	27% 4 8% 30% 28% 4	2090
October	1st to 10th	Night	19% 3 7% 19% 47% 4	3790
	11th to 20th	Night	21% 2 6% 28% 31% 12%	3779
	21st to end	Night	34% 3 8% 28% 25% 2	4120
November	1st to 10th	Night	26% 4 14% 28% 23% 6%	2374
	11th to 20th	Night	33% 3 9% 30% 21% 4	2711
	21st to end	Night	37% 3 11% 28% 18% 2	2800
December	1st to 10th	Night	29% 4 14% 37% 15% 1	4580
	11th to 20th	Night	39% 3 14% 30% 13% 1	5201
	21st to end	Night	60% 4 10% 19% 6% 1	6922

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	23% 13% 32% 25% 6%	300
	11th to 20th	Day	19% 17% 40% 21% 2	300
	21st to end	Day	13% 12% 46% 26% 3	330
February	1st to 10th	Day	20% 18% 43% 17% 2	300
	11th to 20th	Day	18% 17% 43% 14% 7% 1	300
	21st to end	Day	16% 19% 39% 22% 4	249
March	1st to 10th	Day	17% 16% 46% 19% 3	300
	11th to 20th	Day	26% 14% 35% 19% 4 1	300
	21st to end	Day	34% 19% 27% 16% 3 1	315
April	1st to 10th	Day	22% 15% 36% 18% 8%	375
	11th to 20th	Day	19% 12% 40% 21% 7% 1	452
	21st to end	Day	23% 13% 34% 20% 8% 1	624
May	1st to 10th	Day	18% 13% 36% 25% 7% 2	653
	11th to 20th	Day	18% 9% 31% 25% 13% 3	675
	21st to end	Day	17% 8% 32% 24% 16% 3	734
June	1st to 10th	Day	6% 4 21% 37% 24% 9%	680
	11th to 20th	Day	7% 4 28% 38% 18% 5%	680
	21st to end	Day	7% 7% 34% 36% 13% 2	680
July	1st to 10th	Day	10% 3 17% 30% 30% 10%	671
	11th to 20th	Day	7% 3 21% 39% 24% 6%	668
	21st to end	Day	7% 2 17% 39% 28% 7%	739
August	1st to 10th	Day	7% 2 17% 39% 28% 6%	676
	11th to 20th	Day	8% 2 18% 40% 26% 6%	665
	21st to end	Day	10% 1 16% 32% 32% 9%	615
September	1st to 10th	Day	14% 2 16% 34% 27% 6%	490
	11th to 20th	Day	7% 4 21% 36% 25% 8%	317
	21st to end	Day	12% 6% 30% 30% 19% 3	300
October	1st to 10th	Day	16% 6% 25% 28% 17% 7%	300
	11th to 20th	Day	10% 19% 39% 22% 8% 2	300
	21st to end	Day	18% 14% 38% 22% 7% 1	330
November	1st to 10th	Day	16% 11% 37% 29% 5% 2	300
	11th to 20th	Day	17% 18% 35% 24% 6% 1	300
	21st to end	Day	19% 13% 35% 24% 8% 1	300
December	1st to 10th	Day	7% 18% 39% 27% 7% 2	300
	11th to 20th	Day	19% 16% 35% 23% 6% 1	300
	21st to end	Day	21% 20% 38% 18% 3	330
January	1st to 10th	Night	13% 12% 38% 30% 7%	1000
	11th to 20th	Night	16% 13% 39% 26% 6%	1000
	21st to end	Night	14% 10% 42% 29% 4	1100
February	1st to 10th	Night	17% 13% 41% 25% 4	1000
	11th to 20th	Night	16% 13% 38% 29% 4	979
	21st to end	Night	15% 14% 43% 22% 5% 1	647
March	1st to 10th	Night	15% 12% 41% 27% 5%	600
	11th to 20th	Night	19% 10% 38% 28% 5% 1	600
	21st to end	Night	26% 9% 41% 19% 4	647
April	1st to 10th	Night	13% 13% 43% 26% 4	570
	11th to 20th	Night	18% 12% 37% 28% 5%	563
	21st to end	Night	18% 10% 38% 27% 7%	570
May	1st to 10th	Night	17% 9% 34% 32% 7% 1	570
	11th to 20th	Night	17% 5% 30% 35% 12% 1	561
	21st to end	Night	10% 7% 30% 39% 12% 2	617
June	1st to 10th	Night	6% 4 23% 44% 22% 1	570
	11th to 20th	Night	7% 4 26% 45% 18% 1	570
	21st to end	Night	4 4 31% 46% 14%	570
July	1st to 10th	Night	8% 2 14% 45% 29% 3	555
	11th to 20th	Night	4 2 16% 48% 28% 2	552
	21st to end	Night	6% 2 13% 47% 30% 2	624
August	1st to 10th	Night	3 1 18% 48% 28% 2	567
	11th to 20th	Night	8% 2 14% 45% 28% 3	564
	21st to end	Night	8% 2 12% 44% 31% 3	627
September	1st to 10th	Night	11% 2 18% 43% 24% 3	570
	11th to 20th	Night	11% 1 20% 43% 23% 2	570
	21st to end	Night	9% 4 24% 42% 19% 2	570
October	1st to 10th	Night	13% 6% 28% 32% 18% 2	750
	11th to 20th	Night	16% 6% 38% 32% 8%	760
	21st to end	Night	19% 10% 34% 29% 7%	836
November	1st to 10th	Night	10% 11% 34% 35% 10%	814
	11th to 20th	Night	15% 13% 38% 28% 7%	1000
	21st to end	Night	18% 10% 36% 29% 7%	1000
December	1st to 10th	Night	13% 14% 36% 30% 7% 1	1000
	11th to 20th	Night	18% 9% 38% 29% 5%	1000
	21st to end	Night	20% 15% 33% 28% 4	1100

Page generated at 2025-03-24 08:04:27. Version ac07

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