Grand Island KOA Journey
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Grand Island KOA Journey clear sky chart from 2005-11-06 to 2024-11-01.

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	9% 7% 2 6% 4 4 4 3 5% 7% 48%	101592
	Night	9% 6% 2 6% 4 3 4 3 5% 7% 51%	97532
Transparency	Day	34% 7% 14% 25% 17% 3	101349
	Night	32% 6% 14% 26% 19% 3	97365
Seeing	Day	13% 10% 32% 30% 13% 2	15760
	Night	11% 9% 36% 34% 9% 1	25620

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% 14% 4 8% 6% 5% 5% 3 5% 6% 38%	2538
	11th to 20th	Day	5% 12% 4 10% 5% 4 4 4 5% 7% 39%	2818
	21st to end	Day	7% 9% 5% 14% 4 3 3 3 4 5% 43%	3135
February	1st to 10th	Day	9% 11% 4 8% 6% 4 5% 4 6% 7% 38%	1710
	11th to 20th	Day	6% 8% 3 7% 4 3 5% 4 6% 7% 47%	1830
	21st to end	Day	8% 8% 2 6% 4 4 4 4 5% 6% 49%	1570
March	1st to 10th	Day	10% 6% 3 5% 3 3 3 3 4 5% 55%	3240
	11th to 20th	Day	12% 7% 2 5% 3 3 3 3 4 6% 52%	3480
	21st to end	Day	15% 10% 2 8% 4 4 4 4 5% 7% 36%	3814
April	1st to 10th	Day	11% 8% 2 5% 4 4 2 3 5% 7% 48%	2156
	11th to 20th	Day	13% 9% 1 6% 4 4 4 3 4 7% 44%	2388
	21st to end	Day	17% 7% 2 5% 5% 4 5% 3 6% 6% 41%	2470
May	1st to 10th	Day	14% 7% 2 6% 3 4 4 4 6% 8% 41%	4120
	11th to 20th	Day	13% 7% 2 6% 4 4 4 3 5% 6% 47%	4082
	21st to end	Day	13% 7% 2 6% 4 4 4 4 5% 7% 42%	4489
June	1st to 10th	Day	6% 4 1 4 4 4 4 5% 6% 9% 54%	2474
	11th to 20th	Day	8% 5% 2 4 5% 3 4 4 6% 7% 51%	2660
	21st to end	Day	6% 4 1 4 4 4 5% 4 7% 10% 52%	2660
July	1st to 10th	Day	10% 6% 2 6% 4 3 4 3 5% 8% 47%	4430
	11th to 20th	Day	5% 5% 2 5% 4 5% 5% 4 6% 8% 51%	4258
	21st to end	Day	4 4 2 5% 4 4 4 4 7% 9% 54%	4466
August	1st to 10th	Day	7% 5% 2 7% 5% 4 5% 4 6% 9% 45%	4103
	11th to 20th	Day	12% 6% 2 6% 4 4 4 3 6% 8% 43%	4041
	21st to end	Day	5% 4 2 5% 4 4 4 3 5% 7% 57%	4441
September	1st to 10th	Day	11% 5% 2 5% 4 3 3 3 4 6% 55%	2142
	11th to 20th	Day	8% 4 2 5% 3 4 3 2 5% 7% 57%	2090
	21st to end	Day	8% 4 1 3 2 3 3 2 5% 6% 60%	2090
October	1st to 10th	Day	14% 5% 2 5% 3 2 3 3 3 5% 55%	2045
	11th to 20th	Day	10% 6% 1 3 3 3 2 2 5% 6% 59%	1900
	21st to end	Day	13% 6% 2 5% 3 3 3 2 5% 5% 54%	1986
November	1st to 10th	Day	7% 5% 1 4 3 4 3 3 6% 8% 56%	1673
	11th to 20th	Day	7% 7% 2 5% 4 3 3 3 4 6% 56%	1710
	21st to end	Day	11% 8% 2 5% 3 3 4 3 5% 7% 50%	1710
December	1st to 10th	Day	6% 7% 3 6% 4 4 4 4 5% 7% 50%	1710
	11th to 20th	Day	6% 9% 3 6% 5% 4 4 3 5% 6% 47%	2161
	21st to end	Day	13% 11% 3 12% 5% 4 4 4 5% 5% 35%	3002
January	1st to 10th	Night	5% 13% 4 12% 6% 4 4 4 6% 6% 37%	4417
	11th to 20th	Night	6% 9% 3 7% 5% 4 5% 4 5% 5% 48%	4144
	21st to end	Night	8% 10% 4 12% 4 4 4 4 5% 5% 40%	4532
February	1st to 10th	Night	9% 10% 4 8% 5% 4 4 4 4 5% 42%	2470
	11th to 20th	Night	5% 8% 3 7% 5% 5% 4 5% 6% 6% 46%	2253
	21st to end	Night	6% 7% 2 6% 4 4 4 3 5% 6% 52%	1884
March	1st to 10th	Night	11% 5% 2 4 3 3 3 2 4 5% 56%	3620
	11th to 20th	Night	9% 6% 2 5% 3 2 3 2 4 6% 59%	3480
	21st to end	Night	15% 8% 3 5% 4 3 4 4 6% 7% 41%	3817
April	1st to 10th	Night	11% 7% 2 5% 4 3 4 3 5% 7% 48%	2020
	11th to 20th	Night	11% 7% 2 5% 4 4 4 4 6% 9% 44%	1738
	21st to end	Night	14% 5% 2 5% 3 3 4 3 5% 7% 48%	1710
May	1st to 10th	Night	19% 7% 2 4 3 3 3 3 5% 6% 44%	2850
	11th to 20th	Night	9% 6% 3 6% 4 4 4 4 5% 7% 48%	2823
	21st to end	Night	13% 6% 2 6% 4 4 4 3 6% 10% 40%	3098
June	1st to 10th	Night	5% 4 2 4 4 3 4 4 7% 10% 53%	1701
	11th to 20th	Night	7% 4 2 4 3 4 3 4 6% 8% 54%	1520
	21st to end	Night	3 4 2 4 4 3 3 4 7% 9% 58%	1520
July	1st to 10th	Night	9% 5% 2 5% 3 3 4 4 6% 7% 54%	2540
	11th to 20th	Night	5% 3 1 4 3 3 5% 4 8% 10% 54%	2708
	21st to end	Night	3 3 1 3 3 3 3 3 6% 10% 61%	3097
August	1st to 10th	Night	4 3 2 5% 3 4 4 4 7% 11% 52%	2836
	11th to 20th	Night	10% 5% 2 6% 4 3 3 3 6% 9% 49%	2798
	21st to end	Night	4 3 1 4 4 4 4 4 5% 11% 56%	3222
September	1st to 10th	Night	9% 2 2 4 2 3 3 3 4 6% 64%	2038
	11th to 20th	Night	7% 3 2 5% 4 3 4 2 4 8% 58%	2090
	21st to end	Night	7% 4 2 3 4 3 4 3 5% 6% 60%	2090
October	1st to 10th	Night	14% 4 1 4 3 3 3 3 5% 6% 54%	2114
	11th to 20th	Night	10% 5% 1 4 3 3 3 3 4 5% 60%	2280
	21st to end	Night	11% 5% 2 4 3 3 2 2 4 6% 57%	2608
November	1st to 10th	Night	4 4 1 3 3 3 3 3 5% 7% 63%	2412
	11th to 20th	Night	7% 5% 2 4 4 4 3 3 5% 7% 56%	2470
	21st to end	Night	9% 6% 2 4 3 3 3 3 4 7% 55%	2470
December	1st to 10th	Night	6% 8% 2 5% 4 4 4 3 5% 7% 52%	2470
	11th to 20th	Night	7% 6% 2 6% 4 4 3 3 5% 7% 53%	3036
	21st to end	Night	15% 11% 3 10% 4 3 3 3 4 6% 39%	4656

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	44% 8% 16% 22% 9% 1	2539
	11th to 20th	Day	42% 8% 17% 18% 13% 2	2818
	21st to end	Day	44% 6% 13% 23% 12% 1	3135
February	1st to 10th	Day	44% 7% 16% 21% 10% 2	1710
	11th to 20th	Day	36% 6% 16% 24% 15% 4	1840
	21st to end	Day	35% 6% 12% 27% 15% 5%	1570
March	1st to 10th	Day	31% 5% 10% 24% 25% 4	3240
	11th to 20th	Day	33% 6% 12% 28% 20% 2	3480
	21st to end	Day	44% 10% 22% 18% 5% 1	3814
April	1st to 10th	Day	35% 6% 15% 26% 16% 2	2156
	11th to 20th	Day	39% 6% 14% 22% 15% 3	2391
	21st to end	Day	42% 8% 13% 24% 14% 1	2470
May	1st to 10th	Day	36% 9% 15% 22% 14% 4	4120
	11th to 20th	Day	36% 9% 12% 27% 16% 1	4086
	21st to end	Day	38% 9% 12% 27% 12% 1	4489
June	1st to 10th	Day	25% 9% 18% 32% 15% 2	2474
	11th to 20th	Day	30% 8% 14% 28% 17% 3	2660
	21st to end	Day	25% 9% 16% 29% 18% 4	2660
July	1st to 10th	Day	34% 5% 12% 28% 20% 2	4361
	11th to 20th	Day	29% 8% 14% 28% 19% 3	4184
	21st to end	Day	24% 8% 16% 25% 22% 6%	4325
August	1st to 10th	Day	33% 8% 15% 24% 15% 4	4090
	11th to 20th	Day	38% 6% 15% 22% 17% 1	4080
	21st to end	Day	27% 6% 14% 24% 22% 7%	4440
September	1st to 10th	Day	31% 6% 12% 24% 21% 7%	2142
	11th to 20th	Day	28% 6% 12% 29% 23% 3	2090
	21st to end	Day	25% 5% 10% 32% 26% 2	2090
October	1st to 10th	Day	32% 5% 8% 26% 27% 2	2045
	11th to 20th	Day	28% 4 10% 29% 21% 8%	1900
	21st to end	Day	33% 4 12% 24% 22% 5%	1986
November	1st to 10th	Day	26% 5% 15% 29% 22% 3	1673
	11th to 20th	Day	30% 5% 11% 26% 24% 4	1710
	21st to end	Day	35% 4 12% 26% 19% 4	1710
December	1st to 10th	Day	33% 6% 16% 28% 14% 2	1710
	11th to 20th	Day	36% 6% 14% 31% 13%	2159
	21st to end	Day	49% 7% 12% 20% 11% 1	3002
January	1st to 10th	Night	44% 7% 13% 23% 13% 1	4417
	11th to 20th	Night	35% 7% 16% 26% 16% 1	4144
	21st to end	Night	44% 7% 11% 21% 15% 1	4532
February	1st to 10th	Night	42% 7% 13% 22% 13% 3	2470
	11th to 20th	Night	35% 7% 15% 24% 15% 3	2253
	21st to end	Night	31% 5% 13% 21% 22% 8%	1884
March	1st to 10th	Night	29% 4 10% 26% 25% 6%	3620
	11th to 20th	Night	27% 5% 10% 26% 28% 4	3480
	21st to end	Night	40% 9% 22% 21% 6% 1	3817
April	1st to 10th	Night	35% 6% 14% 23% 19% 2	2020
	11th to 20th	Night	35% 7% 15% 26% 15% 2	1738
	21st to end	Night	34% 8% 12% 26% 17% 2	1710
May	1st to 10th	Night	39% 6% 12% 26% 15% 3	2850
	11th to 20th	Night	33% 9% 15% 25% 19%	2824
	21st to end	Night	35% 12% 16% 22% 14% 1	3099
June	1st to 10th	Night	23% 11% 18% 29% 17% 2	1701
	11th to 20th	Night	27% 7% 15% 27% 18% 6%	1520
	21st to end	Night	21% 7% 18% 30% 21% 4	1520
July	1st to 10th	Night	29% 6% 14% 31% 18% 3	2500
	11th to 20th	Night	23% 6% 16% 32% 19% 3	2659
	21st to end	Night	17% 7% 18% 27% 25% 7%	2999
August	1st to 10th	Night	24% 7% 18% 27% 19% 5%	2826
	11th to 20th	Night	32% 6% 18% 27% 15% 1	2825
	21st to end	Night	23% 6% 16% 28% 17% 9%	3222
September	1st to 10th	Night	22% 5% 10% 28% 25% 10%	2038
	11th to 20th	Night	25% 5% 11% 30% 24% 5%	2090
	21st to end	Night	25% 5% 10% 27% 29% 4	2090
October	1st to 10th	Night	30% 6% 11% 24% 26% 4	2114
	11th to 20th	Night	27% 5% 8% 26% 26% 8%	2280
	21st to end	Night	29% 4 12% 26% 23% 6%	2608
November	1st to 10th	Night	20% 5% 13% 29% 26% 6%	2412
	11th to 20th	Night	28% 4 11% 29% 24% 4	2470
	21st to end	Night	29% 4 13% 27% 23% 4	2470
December	1st to 10th	Night	30% 6% 14% 30% 18% 2	2470
	11th to 20th	Night	30% 5% 13% 36% 16% 1	3037
	21st to end	Night	45% 6% 12% 25% 11% 1	4656

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	16% 16% 35% 24% 7% 1	270
	11th to 20th	Day	16% 17% 33% 26% 7% 1	270
	21st to end	Day	14% 11% 44% 23% 7% 1	297
February	1st to 10th	Day	14% 14% 45% 21% 6%	270
	11th to 20th	Day	11% 10% 46% 25% 6% 1	270
	21st to end	Day	14% 17% 49% 15% 5%	225
March	1st to 10th	Day	13% 13% 46% 23% 4 1	270
	11th to 20th	Day	23% 12% 35% 21% 9%	270
	21st to end	Day	25% 16% 39% 16% 4	297
April	1st to 10th	Day	18% 21% 40% 18% 4	336
	11th to 20th	Day	20% 14% 37% 25% 5%	589
	21st to end	Day	21% 17% 32% 20% 9% 2	650
May	1st to 10th	Day	16% 13% 34% 27% 9% 1	653
	11th to 20th	Day	17% 11% 32% 25% 11% 3	675
	21st to end	Day	15% 10% 32% 29% 12% 1	734
June	1st to 10th	Day	5% 7% 27% 36% 20% 5%	680
	11th to 20th	Day	10% 7% 35% 32% 14% 2	680
	21st to end	Day	7% 8% 33% 34% 17% 2	680
July	1st to 10th	Day	9% 4 19% 39% 25% 5%	671
	11th to 20th	Day	5% 2 20% 45% 23% 5%	668
	21st to end	Day	6% 3 20% 40% 27% 4	739
August	1st to 10th	Day	8% 3 19% 46% 22% 3	676
	11th to 20th	Day	7% 5% 20% 43% 22% 2	665
	21st to end	Day	9% 3 23% 39% 23% 4	696
September	1st to 10th	Day	14% 4 27% 37% 14% 4	352
	11th to 20th	Day	6% 6% 31% 38% 14% 5%	300
	21st to end	Day	14% 9% 29% 27% 16% 5%	300
October	1st to 10th	Day	21% 8% 25% 32% 10% 4	300
	11th to 20th	Day	12% 14% 40% 23% 10% 1	300
	21st to end	Day	16% 19% 32% 25% 8% 1	330
November	1st to 10th	Day	11% 17% 40% 21% 8% 2	270
	11th to 20th	Day	9% 16% 47% 20% 7%	270
	21st to end	Day	22% 13% 33% 20% 10% 1	270
December	1st to 10th	Day	7% 11% 43% 32% 5% 1	270
	11th to 20th	Day	15% 11% 40% 28% 6%	270
	21st to end	Day	19% 12% 48% 20% 2	297
January	1st to 10th	Night	11% 12% 37% 33% 6% 1	950
	11th to 20th	Night	12% 12% 40% 29% 6% 1	950
	21st to end	Night	11% 9% 42% 31% 7%	1045
February	1st to 10th	Night	13% 12% 43% 27% 4	950
	11th to 20th	Night	10% 11% 43% 31% 5%	779
	21st to end	Night	10% 13% 48% 24% 5%	628
March	1st to 10th	Night	12% 14% 42% 28% 3 1	698
	11th to 20th	Night	16% 11% 40% 27% 5% 1	570
	21st to end	Night	18% 13% 40% 24% 4	627
April	1st to 10th	Night	16% 13% 42% 26% 3	570
	11th to 20th	Night	15% 13% 44% 24% 3	563
	21st to end	Night	18% 12% 32% 31% 6% 1	570
May	1st to 10th	Night	18% 10% 35% 30% 7%	570
	11th to 20th	Night	14% 8% 38% 32% 8%	561
	21st to end	Night	14% 8% 35% 31% 11%	617
June	1st to 10th	Night	7% 6% 27% 44% 14% 2	570
	11th to 20th	Night	8% 5% 38% 39% 10%	570
	21st to end	Night	5% 5% 34% 44% 13%	570
July	1st to 10th	Night	6% 3 21% 45% 24% 1	555
	11th to 20th	Night	3 2 21% 53% 21% 1	552
	21st to end	Night	4 2 19% 51% 24%	624
August	1st to 10th	Night	6% 2 20% 50% 20% 2	567
	11th to 20th	Night	7% 2 24% 50% 17%	564
	21st to end	Night	7% 3 26% 42% 20% 2	627
September	1st to 10th	Night	10% 2 28% 43% 16% 1	570
	11th to 20th	Night	8% 4 34% 38% 15% 1	570
	21st to end	Night	8% 7% 35% 34% 15% 1	570
October	1st to 10th	Night	16% 8% 32% 32% 12%	594
	11th to 20th	Night	13% 11% 39% 31% 7%	760
	21st to end	Night	14% 13% 32% 31% 10%	936
November	1st to 10th	Night	7% 10% 37% 39% 6% 1	928
	11th to 20th	Night	10% 11% 42% 30% 7%	950
	21st to end	Night	12% 11% 37% 31% 10%	950
December	1st to 10th	Night	10% 11% 44% 29% 5%	950
	11th to 20th	Night	13% 9% 42% 31% 5%	950
	21st to end	Night	16% 13% 38% 28% 5%	1045

Page generated at 2024-10-29 10:20:45. Version ac07

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