IU Kokomo Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the IU Kokomo Observatory clear sky chart from 2005-11-06 to 2024-01-13.

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% 9% 4 6% 6% 3 5% 5% 5% 7% 36%	74855
	Night	15% 9% 4 7% 5% 3 4 4 5% 6% 37%	74889
Transparency	Day	48% 4 12% 22% 12% 2	74560
	Night	48% 4 11% 22% 14% 2	74705
Seeing	Day	18% 10% 27% 24% 15% 6%	14474
	Night	19% 9% 29% 29% 13% 1	24419

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	17% 14% 7% 10% 6% 3 6% 4 5% 5% 23%	1517
	11th to 20th	Day	18% 17% 7% 9% 7% 4 5% 4 4 4 20%	1456
	21st to end	Day	16% 18% 7% 9% 6% 3 5% 4 5% 6% 20%	1624
February	1st to 10th	Day	18% 13% 7% 10% 8% 4 5% 4 4 4 23%	1778
	11th to 20th	Day	16% 12% 5% 8% 9% 4 4 5% 4 6% 27%	1748
	21st to end	Day	17% 14% 8% 8% 5% 2 4 6% 4 5% 28%	1480
March	1st to 10th	Day	17% 13% 5% 8% 6% 3 5% 4 4 7% 29%	1800
	11th to 20th	Day	17% 10% 4 7% 6% 3 5% 4 6% 7% 30%	1909
	21st to end	Day	22% 12% 5% 7% 5% 2 4 4 4 6% 27%	2272
April	1st to 10th	Day	16% 9% 4 7% 6% 3 5% 5% 5% 7% 34%	2160
	11th to 20th	Day	18% 10% 3 5% 5% 3 4 4 6% 7% 36%	2134
	21st to end	Day	20% 9% 3 6% 5% 4 4 4 5% 7% 34%	2326
May	1st to 10th	Day	17% 9% 4 6% 6% 5% 5% 5% 5% 7% 31%	2340
	11th to 20th	Day	20% 8% 4 6% 5% 3 4 5% 5% 7% 33%	2301
	21st to end	Day	12% 6% 3 5% 6% 4 6% 5% 6% 9% 38%	2624
June	1st to 10th	Day	11% 5% 2 6% 7% 4 4 5% 6% 7% 42%	2520
	11th to 20th	Day	10% 4 2 4 5% 4 6% 5% 6% 9% 45%	2520
	21st to end	Day	11% 5% 3 5% 6% 4 6% 6% 6% 9% 40%	2520
July	1st to 10th	Day	9% 6% 2 5% 5% 3 6% 6% 7% 10% 42%	2520
	11th to 20th	Day	7% 4 2 5% 6% 3 5% 5% 7% 9% 47%	2520
	21st to end	Day	9% 4 2 4 6% 4 6% 7% 7% 10% 42%	2697
August	1st to 10th	Day	6% 4 2 6% 5% 3 6% 6% 7% 9% 46%	2327
	11th to 20th	Day	10% 5% 2 4 6% 4 5% 6% 6% 9% 43%	2231
	21st to end	Day	8% 4 2 6% 6% 2 5% 5% 6% 9% 48%	2376
September	1st to 10th	Day	11% 6% 3 5% 5% 3 5% 4 6% 7% 45%	2134
	11th to 20th	Day	11% 4 2 5% 5% 3 5% 5% 5% 8% 47%	1980
	21st to end	Day	12% 5% 2 4 4 3 5% 4 6% 7% 47%	1980
October	1st to 10th	Day	13% 6% 3 5% 5% 3 4 4 5% 7% 45%	1980
	11th to 20th	Day	16% 7% 3 5% 5% 3 5% 5% 5% 6% 40%	1819
	21st to end	Day	19% 9% 4 7% 6% 3 4 5% 5% 7% 31%	1782
November	1st to 10th	Day	11% 7% 2 5% 4 2 4 4 5% 6% 49%	1672
	11th to 20th	Day	17% 11% 5% 6% 5% 4 4 3 5% 6% 34%	1710
	21st to end	Day	20% 10% 3 8% 5% 2 5% 4 4 5% 33%	1710
December	1st to 10th	Day	17% 15% 6% 10% 6% 3 4 4 3 6% 26%	1687
	11th to 20th	Day	16% 14% 7% 10% 7% 4 5% 3 4 5% 26%	1918
	21st to end	Day	25% 20% 9% 11% 6% 3 4 3 3 4 13%	2783
January	1st to 10th	Night	17% 13% 6% 11% 7% 4 3 3 3 5% 27%	2648
	11th to 20th	Night	17% 17% 6% 10% 6% 4 4 3 3 4 25%	2549
	21st to end	Night	15% 14% 7% 10% 7% 4 4 4 4 5% 25%	2729
February	1st to 10th	Night	20% 14% 5% 9% 6% 3 4 4 4 5% 26%	2179
	11th to 20th	Night	14% 12% 5% 9% 7% 4 4 4 5% 5% 32%	2098
	21st to end	Night	20% 13% 5% 9% 5% 2 4 4 4 6% 30%	1776
March	1st to 10th	Night	16% 10% 5% 7% 6% 4 5% 4 5% 5% 34%	2160
	11th to 20th	Night	14% 9% 5% 5% 5% 3 4 4 6% 7% 37%	2050
	21st to end	Night	21% 10% 3 7% 5% 3 4 5% 4 6% 32%	2098
April	1st to 10th	Night	13% 8% 4 6% 5% 4 5% 5% 6% 6% 40%	1800
	11th to 20th	Night	17% 8% 3 5% 5% 2 4 4 4 7% 39%	1775
	21st to end	Night	19% 7% 3 5% 5% 3 5% 5% 5% 7% 36%	1632
May	1st to 10th	Night	19% 7% 3 6% 7% 4 4 4 6% 8% 32%	1620
	11th to 20th	Night	19% 6% 3 5% 5% 3 4 5% 5% 7% 38%	1592
	21st to end	Night	9% 4 2 6% 6% 3 6% 6% 7% 9% 42%	1648
June	1st to 10th	Night	9% 4 2 6% 5% 3 5% 5% 5% 6% 50%	1440
	11th to 20th	Night	8% 4 2 5% 4 3 4 6% 6% 9% 48%	1440
	21st to end	Night	9% 7% 2 5% 5% 3 5% 5% 5% 9% 45%	1440
July	1st to 10th	Night	7% 5% 3 5% 5% 4 4 5% 6% 11% 46%	1440
	11th to 20th	Night	8% 3 2 3 5% 3 3 5% 7% 9% 54%	1440
	21st to end	Night	8% 4 2 5% 5% 3 4 4 5% 8% 52%	1619
August	1st to 10th	Night	7% 4 2 5% 4 4 4 5% 7% 9% 50%	1611
	11th to 20th	Night	7% 4 3 6% 6% 2 4 6% 6% 8% 49%	1667
	21st to end	Night	8% 3 2 6% 5% 2 4 4 5% 8% 53%	1980
September	1st to 10th	Night	13% 5% 2 5% 5% 3 3 4 4 7% 48%	1807
	11th to 20th	Night	9% 4 2 4 4 2 3 4 4 7% 57%	1980
	21st to end	Night	10% 5% 2 4 4 3 4 4 5% 7% 51%	1980
October	1st to 10th	Night	11% 6% 2 4 4 3 3 4 5% 6% 51%	1980
	11th to 20th	Night	17% 6% 3 5% 4 3 4 3 5% 7% 43%	2139
	21st to end	Night	19% 8% 3 6% 5% 3 4 4 4 6% 38%	2574
November	1st to 10th	Night	12% 7% 3 5% 4 2 3 5% 5% 6% 47%	2406
	11th to 20th	Night	15% 10% 4 6% 4 3 4 4 5% 7% 39%	2470
	21st to end	Night	19% 12% 5% 7% 6% 3 4 4 4 6% 31%	2470
December	1st to 10th	Night	17% 13% 5% 9% 7% 3 4 3 5% 6% 29%	2489
	11th to 20th	Night	17% 13% 6% 8% 5% 3 4 5% 4 6% 28%	3279
	21st to end	Night	24% 18% 8% 9% 6% 3 4 4 4 4 15%	4884

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	64% 3 9% 17% 8%	1518
	11th to 20th	Day	68% 4 11% 12% 5%	1456
	21st to end	Day	65% 3 12% 13% 6% 1	1624
February	1st to 10th	Day	66% 3 9% 14% 7% 1	1778
	11th to 20th	Day	58% 4 10% 20% 7% 1	1758
	21st to end	Day	59% 5% 11% 18% 6% 2	1480
March	1st to 10th	Day	57% 3 10% 21% 9%	1800
	11th to 20th	Day	53% 4 14% 18% 10% 1	1909
	21st to end	Day	59% 4 13% 19% 4 1	2272
April	1st to 10th	Day	50% 5% 12% 20% 13% 1	2160
	11th to 20th	Day	48% 4 10% 23% 11% 4	2134
	21st to end	Day	51% 4 11% 21% 10% 3	2326
May	1st to 10th	Day	52% 5% 13% 20% 9%	2340
	11th to 20th	Day	51% 4 12% 19% 12% 1	2305
	21st to end	Day	42% 6% 13% 23% 14% 2	2624
June	1st to 10th	Day	40% 5% 11% 26% 16% 3	2520
	11th to 20th	Day	36% 5% 12% 25% 20% 3	2520
	21st to end	Day	40% 7% 16% 19% 15% 3	2520
July	1st to 10th	Day	37% 5% 13% 24% 16% 4	2451
	11th to 20th	Day	33% 5% 14% 28% 17% 2	2445
	21st to end	Day	35% 7% 15% 25% 15% 3	2547
August	1st to 10th	Day	32% 7% 16% 29% 15% 1	2314
	11th to 20th	Day	37% 6% 14% 26% 16% 1	2231
	21st to end	Day	33% 5% 12% 25% 18% 6%	2376
September	1st to 10th	Day	38% 4 13% 23% 16% 4	2134
	11th to 20th	Day	35% 5% 10% 28% 21% 2	1980
	21st to end	Day	35% 5% 11% 25% 22% 2	1980
October	1st to 10th	Day	39% 4 11% 25% 18% 3	1980
	11th to 20th	Day	42% 5% 10% 24% 18% 1	1819
	21st to end	Day	53% 4 10% 21% 11% 1	1782
November	1st to 10th	Day	36% 3 14% 27% 17% 2	1672
	11th to 20th	Day	52% 2 11% 21% 12% 2	1710
	21st to end	Day	55% 4 11% 21% 9% 1	1710
December	1st to 10th	Day	62% 3 10% 18% 7%	1687
	11th to 20th	Day	62% 2 9% 23% 3	1915
	21st to end	Day	78% 3 7% 8% 4	2783
January	1st to 10th	Night	61% 3 7% 18% 10%	2648
	11th to 20th	Night	64% 3 10% 16% 7% 1	2549
	21st to end	Night	62% 3 10% 16% 8% 1	2729
February	1st to 10th	Night	62% 3 12% 14% 8% 1	2179
	11th to 20th	Night	55% 3 10% 19% 12% 1	2099
	21st to end	Night	57% 3 10% 18% 9% 2	1776
March	1st to 10th	Night	53% 4 9% 21% 11% 1	2160
	11th to 20th	Night	46% 4 11% 24% 12% 3	2050
	21st to end	Night	53% 5% 11% 21% 9% 1	2098
April	1st to 10th	Night	44% 4 13% 25% 13% 2	1800
	11th to 20th	Night	46% 3 9% 22% 15% 4	1775
	21st to end	Night	47% 5% 9% 22% 13% 4	1632
May	1st to 10th	Night	50% 4 13% 19% 11% 2	1620
	11th to 20th	Night	45% 6% 12% 23% 13% 2	1593
	21st to end	Night	36% 8% 15% 21% 15% 5%	1649
June	1st to 10th	Night	34% 5% 10% 27% 20% 3	1440
	11th to 20th	Night	32% 5% 13% 25% 22% 4	1440
	21st to end	Night	36% 5% 16% 24% 15% 4	1440
July	1st to 10th	Night	35% 6% 15% 23% 16% 6%	1400
	11th to 20th	Night	27% 5% 15% 29% 21% 3	1392
	21st to end	Night	30% 4 16% 26% 18% 5%	1529
August	1st to 10th	Night	29% 6% 14% 29% 20% 1	1600
	11th to 20th	Night	32% 6% 15% 25% 21% 2	1667
	21st to end	Night	30% 4 13% 26% 21% 5%	1980
September	1st to 10th	Night	36% 5% 12% 23% 17% 6%	1807
	11th to 20th	Night	29% 4 9% 29% 27% 3	1980
	21st to end	Night	33% 5% 11% 24% 24% 3	1980
October	1st to 10th	Night	34% 4 9% 29% 21% 3	1980
	11th to 20th	Night	43% 2 9% 25% 19% 2	2139
	21st to end	Night	48% 4 8% 24% 14% 2	2574
November	1st to 10th	Night	38% 4 9% 26% 20% 3	2406
	11th to 20th	Night	46% 3 10% 23% 15% 3	2470
	21st to end	Night	56% 3 10% 23% 9%	2470
December	1st to 10th	Night	58% 3 10% 19% 9% 1	2489
	11th to 20th	Night	58% 3 10% 20% 8% 1	3281
	21st to end	Night	74% 3 9% 10% 5%	4884

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	25% 17% 39% 14% 4 1	270
	11th to 20th	Day	29% 13% 39% 15% 2 1	246
	21st to end	Day	27% 18% 34% 16% 5%	264
February	1st to 10th	Day	26% 18% 40% 14% 3	240
	11th to 20th	Day	28% 19% 32% 16% 4 1	240
	21st to end	Day	27% 20% 38% 14% 2	198
March	1st to 10th	Day	23% 20% 37% 16% 4	240
	11th to 20th	Day	29% 9% 37% 19% 6% 1	349
	21st to end	Day	33% 14% 28% 17% 7% 1	462
April	1st to 10th	Day	23% 14% 32% 21% 9% 2	420
	11th to 20th	Day	23% 16% 29% 20% 9% 3	412
	21st to end	Day	29% 14% 30% 17% 9% 2	420
May	1st to 10th	Day	22% 13% 33% 21% 8% 3	423
	11th to 20th	Day	23% 7% 29% 23% 13% 5%	447
	21st to end	Day	14% 6% 28% 24% 18% 9%	578
June	1st to 10th	Day	10% 6% 30% 29% 21% 5%	630
	11th to 20th	Day	12% 6% 26% 30% 20% 6%	630
	21st to end	Day	13% 4 28% 29% 18% 7%	630
July	1st to 10th	Day	11% 3 17% 27% 25% 16%	621
	11th to 20th	Day	7% 3 22% 33% 22% 13%	618
	21st to end	Day	9% 4 18% 30% 27% 12%	638
August	1st to 10th	Day	7% 4 12% 32% 28% 17%	446
	11th to 20th	Day	10% 2 18% 30% 26% 13%	439
	21st to end	Day	7% 3 16% 31% 31% 12%	495
September	1st to 10th	Day	13% 4 16% 31% 28% 8%	450
	11th to 20th	Day	11% 2 16% 26% 30% 14%	450
	21st to end	Day	14% 9% 22% 24% 24% 8%	450
October	1st to 10th	Day	14% 7% 25% 30% 16% 8%	450
	11th to 20th	Day	17% 19% 30% 24% 10%	374
	21st to end	Day	29% 14% 36% 19% 1 1	297
November	1st to 10th	Day	13% 17% 33% 23% 12% 3	270
	11th to 20th	Day	26% 16% 31% 18% 8% 1	270
	21st to end	Day	29% 12% 36% 19% 4	270
December	1st to 10th	Day	24% 18% 37% 14% 6% 1	270
	11th to 20th	Day	20% 16% 39% 19% 6%	270
	21st to end	Day	29% 19% 35% 15% 2	297
January	1st to 10th	Night	24% 16% 35% 21% 4	950
	11th to 20th	Night	24% 13% 38% 21% 4	911
	21st to end	Night	22% 15% 36% 25% 3	947
February	1st to 10th	Night	29% 12% 33% 24% 3	720
	11th to 20th	Night	21% 15% 36% 24% 3	703
	21st to end	Night	27% 13% 37% 20% 3	592
March	1st to 10th	Night	19% 16% 33% 26% 6%	720
	11th to 20th	Night	19% 10% 38% 25% 6% 1	720
	21st to end	Night	26% 10% 32% 25% 7%	712
April	1st to 10th	Night	17% 11% 39% 26% 7% 1	540
	11th to 20th	Night	21% 12% 32% 25% 9% 1	533
	21st to end	Night	23% 9% 35% 24% 8% 1	540
May	1st to 10th	Night	20% 8% 33% 31% 8%	540
	11th to 20th	Night	21% 5% 24% 32% 15% 2	531
	21st to end	Night	11% 3 23% 41% 20% 2	584
June	1st to 10th	Night	8% 3 25% 45% 18% 1	540
	11th to 20th	Night	10% 3 22% 42% 21% 1	540
	21st to end	Night	10% 3 23% 40% 23% 1	540
July	1st to 10th	Night	9% 2 14% 40% 29% 6%	525
	11th to 20th	Night	7% 3 18% 37% 31% 5%	522
	21st to end	Night	8% 2 14% 41% 33% 2	591
August	1st to 10th	Night	8% 1 13% 42% 31% 5%	537
	11th to 20th	Night	7% 2 14% 42% 30% 6%	534
	21st to end	Night	8% 2 15% 34% 35% 5%	594
September	1st to 10th	Night	14% 3 16% 36% 27% 4	547
	11th to 20th	Night	12% 3 16% 34% 33% 3	720
	21st to end	Night	11% 7% 20% 36% 23% 2	720
October	1st to 10th	Night	13% 6% 23% 35% 19% 3	720
	11th to 20th	Night	20% 12% 29% 28% 11% 1	720
	21st to end	Night	24% 12% 32% 25% 7%	792
November	1st to 10th	Night	18% 8% 35% 27% 11% 1	740
	11th to 20th	Night	21% 16% 31% 24% 7% 1	760
	21st to end	Night	25% 13% 31% 24% 7%	760
December	1st to 10th	Night	25% 12% 36% 23% 4 1	779
	11th to 20th	Night	24% 13% 33% 24% 6% 1	950
	21st to end	Night	28% 16% 31% 21% 3	1045

Page generated at 2024-01-10 01:25:00. Version ac07

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