Goshen College
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Goshen College clear sky chart from 2005-11-06 to 2026-02-16.

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	14% 10% 4 9% 5% 5% 5% 4 5% 7% 33%	130473
	Night	14% 11% 4 9% 5% 4 4 4 5% 6% 32%	130587
Transparency	Day	49% 5% 11% 21% 12% 1	134028
	Night	50% 5% 11% 20% 12% 1	135107
Seeing	Day	18% 11% 27% 24% 14% 6%	17409
	Night	19% 10% 28% 29% 12% 1	27364

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% 17% 9% 21% 6% 5% 4 3 4 4 12%	4691
	11th to 20th	Day	10% 14% 9% 14% 8% 9% 6% 4 6% 5% 14%	4710
	21st to end	Day	18% 16% 7% 13% 7% 6% 5% 3 4 4 17%	5212
February	1st to 10th	Day	15% 14% 6% 12% 7% 6% 4 3 6% 5% 21%	2016
	11th to 20th	Day	14% 12% 5% 14% 8% 6% 4 4 5% 6% 23%	1998
	21st to end	Day	16% 15% 6% 11% 5% 4 4 3 5% 6% 25%	1650
March	1st to 10th	Day	18% 12% 6% 11% 5% 4 3 2 4 5% 29%	4480
	11th to 20th	Day	10% 10% 6% 7% 4 4 5% 4 6% 8% 37%	4835
	21st to end	Day	18% 15% 6% 11% 6% 5% 4 3 5% 5% 21%	5681
April	1st to 10th	Day	17% 13% 4 8% 5% 4 4 3 5% 6% 30%	2400
	11th to 20th	Day	16% 10% 3 7% 5% 5% 5% 4 4 7% 35%	2399
	21st to end	Day	17% 9% 3 7% 5% 4 4 3 6% 8% 35%	2600
May	1st to 10th	Day	20% 9% 3 8% 5% 4 5% 4 5% 6% 32%	5862
	11th to 20th	Day	14% 7% 2 6% 4 5% 5% 4 6% 8% 38%	5861
	21st to end	Day	14% 6% 2 6% 4 4 4 4 6% 8% 41%	6787
June	1st to 10th	Day	10% 6% 2 6% 5% 4 5% 5% 6% 9% 42%	2800
	11th to 20th	Day	10% 5% 2 5% 5% 5% 5% 5% 7% 7% 44%	2800
	21st to end	Day	11% 5% 2 6% 4 6% 6% 5% 7% 8% 41%	2800
July	1st to 10th	Day	10% 6% 3 6% 5% 4 5% 5% 7% 9% 40%	6360
	11th to 20th	Day	8% 5% 2 6% 4 4 5% 4 7% 11% 42%	6360
	21st to end	Day	9% 6% 2 7% 5% 6% 5% 4 7% 8% 40%	6863
August	1st to 10th	Day	9% 5% 2 6% 4 4 5% 4 6% 9% 47%	4234
	11th to 20th	Day	9% 6% 2 6% 5% 5% 5% 4 6% 8% 45%	4141
	21st to end	Day	7% 5% 2 6% 4 4 5% 4 6% 9% 48%	4312
September	1st to 10th	Day	10% 6% 2 5% 5% 5% 4 3 5% 8% 47%	2365
	11th to 20th	Day	10% 4 2 5% 4 4 4 4 6% 8% 49%	2200
	21st to end	Day	13% 7% 3 7% 4 4 4 4 5% 8% 42%	2200
October	1st to 10th	Day	14% 7% 3 6% 4 3 4 3 5% 7% 44%	2200
	11th to 20th	Day	18% 8% 2 7% 5% 4 4 4 5% 7% 36%	1989
	21st to end	Day	19% 11% 3 8% 5% 5% 4 5% 5% 7% 28%	1980
November	1st to 10th	Day	12% 9% 3 7% 5% 4 4 4 5% 7% 40%	1852
	11th to 20th	Day	16% 16% 5% 8% 5% 4 3 3 5% 5% 30%	1890
	21st to end	Day	20% 15% 5% 10% 4 4 4 3 4 5% 24%	1890
December	1st to 10th	Day	10% 16% 6% 15% 5% 4 4 3 5% 6% 25%	2897
	11th to 20th	Day	16% 18% 10% 13% 5% 5% 4 3 4 5% 17%	3088
	21st to end	Day	26% 21% 7% 14% 6% 4 3 2 3 4 10%	4070
January	1st to 10th	Night	13% 17% 7% 19% 6% 5% 4 3 4 4 17%	8232
	11th to 20th	Night	11% 17% 8% 17% 7% 6% 5% 5% 6% 5% 13%	8280
	21st to end	Night	17% 14% 6% 11% 7% 7% 5% 4 4 5% 21%	8984
February	1st to 10th	Night	17% 15% 4 10% 7% 5% 4 3 4 6% 25%	2601
	11th to 20th	Night	14% 13% 5% 12% 6% 5% 4 3 5% 7% 26%	2399
	21st to end	Night	19% 13% 5% 10% 5% 5% 4 3 4 5% 27%	1980
March	1st to 10th	Night	15% 11% 4 9% 5% 4 4 3 4 6% 34%	5373
	11th to 20th	Night	12% 8% 3 6% 5% 4 4 3 5% 7% 42%	5123
	21st to end	Night	18% 11% 4 8% 4 4 3 3 5% 6% 32%	5290
April	1st to 10th	Night	16% 11% 2 6% 4 4 5% 4 5% 7% 36%	2000
	11th to 20th	Night	19% 8% 3 6% 4 5% 4 3 5% 5% 37%	1949
	21st to end	Night	16% 9% 3 6% 5% 4 5% 4 5% 6% 37%	1800
May	1st to 10th	Night	19% 11% 3 7% 5% 4 4 3 5% 6% 32%	4033
	11th to 20th	Night	16% 7% 2 7% 4 4 4 3 5% 8% 40%	4032
	21st to end	Night	17% 7% 2 7% 4 3 4 4 5% 6% 41%	4080
June	1st to 10th	Night	10% 5% 2 5% 4 3 4 4 6% 9% 47%	1600
	11th to 20th	Night	9% 5% 2 6% 5% 4 5% 5% 6% 9% 45%	1600
	21st to end	Night	9% 6% 3 6% 4 4 5% 4 7% 9% 44%	1600
July	1st to 10th	Night	8% 5% 2 5% 5% 4 4 4 6% 11% 45%	3618
	11th to 20th	Night	7% 5% 2 6% 4 4 4 4 6% 8% 49%	3617
	21st to end	Night	10% 6% 2 6% 4 4 5% 4 6% 8% 44%	3990
August	1st to 10th	Night	10% 7% 2 6% 4 4 4 5% 6% 8% 45%	2915
	11th to 20th	Night	8% 6% 2 5% 4 4 5% 4 6% 8% 49%	2904
	21st to end	Night	9% 6% 2 6% 4 4 4 3 5% 7% 50%	3586
September	1st to 10th	Night	11% 5% 2 5% 4 3 3 3 5% 6% 53%	2015
	11th to 20th	Night	9% 5% 2 5% 4 3 3 3 4 8% 56%	2200
	21st to end	Night	14% 7% 3 7% 3 4 3 3 5% 6% 47%	2200
October	1st to 10th	Night	12% 6% 2 5% 3 3 4 3 4 6% 50%	2200
	11th to 20th	Night	18% 9% 3 5% 4 4 4 2 4 6% 39%	2407
	21st to end	Night	21% 9% 3 7% 4 4 4 3 4 6% 36%	2860
November	1st to 10th	Night	12% 11% 3 7% 4 5% 4 4 5% 6% 40%	2666
	11th to 20th	Night	15% 14% 4 8% 4 4 4 5% 6% 7% 30%	2730
	21st to end	Night	20% 17% 4 8% 5% 4 4 3 5% 6% 25%	2730
December	1st to 10th	Night	13% 12% 5% 13% 6% 6% 5% 4 6% 6% 23%	4504
	11th to 20th	Night	17% 19% 8% 13% 7% 5% 4 3 4 5% 15%	5339
	21st to end	Night	26% 20% 7% 11% 5% 5% 4 3 4 5% 11%	7150

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	74% 5% 10% 9% 2	4692
	11th to 20th	Day	70% 4 8% 10% 8%	4710
	21st to end	Day	72% 3 9% 11% 5%	5212
February	1st to 10th	Day	64% 5% 11% 13% 7% 1	2016
	11th to 20th	Day	62% 6% 9% 16% 8%	2008
	21st to end	Day	60% 4 11% 16% 7% 2	1650
March	1st to 10th	Day	58% 4 9% 21% 8%	4480
	11th to 20th	Day	44% 5% 14% 29% 7% 1	4835
	21st to end	Day	64% 5% 10% 14% 5% 1	5683
April	1st to 10th	Day	54% 5% 10% 19% 12%	2400
	11th to 20th	Day	49% 5% 11% 21% 12% 2	2399
	21st to end	Day	47% 5% 13% 20% 12% 2	2600
May	1st to 10th	Day	50% 6% 11% 18% 13% 1	5897
	11th to 20th	Day	43% 7% 14% 23% 12% 1	5865
	21st to end	Day	39% 6% 11% 25% 18% 1	6801
June	1st to 10th	Day	38% 6% 12% 26% 17% 2	2800
	11th to 20th	Day	37% 7% 11% 25% 18% 2	2800
	21st to end	Day	38% 8% 15% 20% 17% 3	2800
July	1st to 10th	Day	38% 6% 12% 25% 16% 2	6291
	11th to 20th	Day	34% 7% 15% 28% 15% 1	6285
	21st to end	Day	39% 7% 12% 23% 17% 2	6668
August	1st to 10th	Day	34% 6% 15% 29% 16% 1	4221
	11th to 20th	Day	35% 6% 13% 28% 17% 1	4180
	21st to end	Day	32% 6% 13% 28% 18% 3	4311
September	1st to 10th	Day	35% 6% 15% 24% 18% 3	2365
	11th to 20th	Day	32% 5% 11% 28% 22% 2	2200
	21st to end	Day	40% 5% 11% 24% 19% 1	2200
October	1st to 10th	Day	29% 4 9% 36% 20% 1	3590
	11th to 20th	Day	40% 4 10% 21% 25%	3205
	21st to end	Day	46% 5% 11% 24% 12% 2	3180
November	1st to 10th	Day	43% 5% 10% 25% 15% 1	1852
	11th to 20th	Day	57% 3 10% 20% 9% 1	1890
	21st to end	Day	63% 4 10% 17% 6%	1890
December	1st to 10th	Day	60% 4 15% 17% 3	2897
	11th to 20th	Day	69% 4 10% 15% 2	3085
	21st to end	Day	80% 3 6% 7% 3	4070
January	1st to 10th	Night	70% 5% 8% 14% 4	8233
	11th to 20th	Night	70% 5% 8% 11% 6%	8280
	21st to end	Night	65% 5% 12% 11% 7%	8984
February	1st to 10th	Night	61% 5% 11% 15% 8% 1	2601
	11th to 20th	Night	58% 5% 9% 20% 8% 1	2400
	21st to end	Night	60% 4 11% 15% 8% 2	1980
March	1st to 10th	Night	51% 4 11% 25% 8% 1	5373
	11th to 20th	Night	40% 6% 11% 28% 12% 2	5123
	21st to end	Night	51% 5% 12% 20% 11% 1	5290
April	1st to 10th	Night	46% 6% 11% 21% 14% 1	2000
	11th to 20th	Night	48% 5% 8% 19% 17% 2	1949
	21st to end	Night	48% 6% 10% 22% 13% 2	1800
May	1st to 10th	Night	52% 6% 10% 18% 14% 2	4060
	11th to 20th	Night	42% 6% 11% 25% 15% 1	4033
	21st to end	Night	41% 6% 11% 21% 19% 2	4088
June	1st to 10th	Night	31% 7% 12% 29% 19% 3	1600
	11th to 20th	Night	35% 7% 13% 24% 20% 2	1600
	21st to end	Night	35% 6% 19% 22% 16% 3	1600
July	1st to 10th	Night	33% 6% 12% 26% 18% 4	3580
	11th to 20th	Night	32% 6% 16% 24% 20% 2	3572
	21st to end	Night	36% 6% 15% 21% 21% 3	3874
August	1st to 10th	Night	35% 7% 13% 28% 15% 1	2904
	11th to 20th	Night	32% 7% 13% 29% 18% 1	2931
	21st to end	Night	33% 5% 10% 30% 20% 3	3586
September	1st to 10th	Night	32% 6% 11% 26% 21% 5%	2015
	11th to 20th	Night	28% 5% 8% 31% 27% 2	2200
	21st to end	Night	38% 5% 9% 27% 19% 2	2200
October	1st to 10th	Night	25% 4 7% 33% 29% 1	3590
	11th to 20th	Night	39% 4 9% 24% 24% 1	3930
	21st to end	Night	38% 4 9% 29% 19% 1	4610
November	1st to 10th	Night	43% 6% 9% 24% 16% 1	2666
	11th to 20th	Night	51% 7% 12% 20% 9% 2	2730
	21st to end	Night	60% 4 11% 18% 7%	2730
December	1st to 10th	Night	58% 5% 15% 17% 4	4504
	11th to 20th	Night	71% 5% 11% 10% 3	5341
	21st to end	Night	76% 4 9% 8% 3	7150

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	21% 20% 33% 20% 5% 1	330
	11th to 20th	Day	24% 20% 37% 14% 4 1	330
	21st to end	Day	27% 17% 34% 18% 3 1	363
February	1st to 10th	Day	24% 19% 35% 17% 4 1	330
	11th to 20th	Day	24% 21% 31% 21% 3 1	315
	21st to end	Day	27% 20% 39% 10% 3	249
March	1st to 10th	Day	24% 20% 36% 16% 4	300
	11th to 20th	Day	25% 15% 31% 21% 6% 1	433
	21st to end	Day	32% 15% 28% 19% 5% 1	550
April	1st to 10th	Day	27% 14% 31% 21% 7% 1	500
	11th to 20th	Day	23% 19% 30% 16% 8% 3	492
	21st to end	Day	25% 13% 30% 20% 10% 2	500
May	1st to 10th	Day	26% 13% 29% 19% 10% 3	503
	11th to 20th	Day	23% 9% 27% 23% 13% 5%	527
	21st to end	Day	14% 8% 29% 27% 16% 8%	719
June	1st to 10th	Day	11% 10% 29% 28% 17% 5%	730
	11th to 20th	Day	14% 7% 27% 29% 19% 5%	730
	21st to end	Day	13% 6% 29% 29% 17% 6%	730
July	1st to 10th	Day	11% 4 19% 29% 22% 15%	721
	11th to 20th	Day	11% 4 24% 30% 20% 11%	718
	21st to end	Day	9% 4 20% 33% 25% 10%	770
August	1st to 10th	Day	10% 3 16% 29% 26% 16%	526
	11th to 20th	Day	11% 5% 18% 32% 26% 8%	519
	21st to end	Day	11% 4 16% 30% 28% 12%	583
September	1st to 10th	Day	13% 6% 20% 26% 24% 11%	530
	11th to 20th	Day	9% 4 15% 24% 32% 16%	530
	21st to end	Day	18% 10% 20% 23% 22% 8%	530
October	1st to 10th	Day	15% 7% 25% 30% 17% 7%	530
	11th to 20th	Day	22% 15% 24% 30% 8% 1	445
	21st to end	Day	28% 11% 40% 18% 3 1	363
November	1st to 10th	Day	16% 16% 34% 23% 8% 2	330
	11th to 20th	Day	27% 18% 31% 17% 6% 1	330
	21st to end	Day	30% 16% 35% 15% 3	330
December	1st to 10th	Day	22% 21% 35% 16% 6% 1	330
	11th to 20th	Day	24% 20% 35% 17% 4	330
	21st to end	Day	28% 21% 35% 14% 2	363
January	1st to 10th	Night	23% 15% 36% 21% 5%	1050
	11th to 20th	Night	24% 18% 34% 20% 4 1	1050
	21st to end	Night	23% 13% 36% 24% 3	1133
February	1st to 10th	Night	26% 10% 35% 25% 4	840
	11th to 20th	Night	21% 14% 37% 25% 3	804
	21st to end	Night	27% 12% 37% 21% 3	660
March	1st to 10th	Night	21% 12% 35% 26% 7% 1	800
	11th to 20th	Night	19% 11% 37% 26% 7%	800
	21st to end	Night	25% 11% 29% 30% 5%	806
April	1st to 10th	Night	19% 15% 33% 26% 7% 1	600
	11th to 20th	Night	24% 10% 34% 26% 6% 1	593
	21st to end	Night	21% 10% 31% 29% 9% 1	600
May	1st to 10th	Night	23% 8% 30% 31% 9%	600
	11th to 20th	Night	21% 5% 30% 30% 13% 1	591
	21st to end	Night	15% 4 25% 39% 17% 1	650
June	1st to 10th	Night	11% 3 26% 45% 14% 1	600
	11th to 20th	Night	11% 4 26% 41% 17% 1	600
	21st to end	Night	11% 4 23% 39% 23% 1	600
July	1st to 10th	Night	7% 2 15% 44% 27% 5%	585
	11th to 20th	Night	9% 3 18% 40% 28% 3	582
	21st to end	Night	7% 1 14% 42% 33% 2	657
August	1st to 10th	Night	9% 2 11% 45% 29% 5%	597
	11th to 20th	Night	8% 2 14% 45% 26% 5%	594
	21st to end	Night	11% 1 15% 36% 33% 4	660
September	1st to 10th	Night	13% 4 16% 37% 28% 3	615
	11th to 20th	Night	11% 3 15% 36% 31% 4	800
	21st to end	Night	17% 6% 22% 32% 19% 5%	800
October	1st to 10th	Night	14% 7% 24% 34% 20% 2	800
	11th to 20th	Night	22% 14% 26% 29% 8% 1	800
	21st to end	Night	25% 12% 31% 24% 7%	880
November	1st to 10th	Night	17% 12% 33% 27% 10% 1	820
	11th to 20th	Night	23% 14% 33% 24% 5% 1	840
	21st to end	Night	27% 13% 31% 24% 4	840
December	1st to 10th	Night	26% 14% 35% 21% 5%	912
	11th to 20th	Night	23% 16% 35% 21% 4	1050
	21st to end	Night	31% 14% 32% 20% 3	1155

Page generated at 2026-02-13 01:42:12. Version ac07

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