Insel Haus
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Insel Haus clear sky chart from 2005-11-06 to 2025-02-25.

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	13% 10% 4 9% 6% 5% 5% 4 5% 7% 33%	108111
	Night	14% 13% 5% 11% 6% 5% 5% 3 5% 6% 27%	110723
Transparency	Day	30% 44% 7% 13% 6%	111649
	Night	34% 42% 7% 11% 5%	115348
Seeing	Day	17% 5% 22% 32% 19% 5%	15880
	Night	20% 8% 25% 30% 14% 2	25558

By Month

Percentage Cloud Cover NE (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	10% 15% 9% 24% 8% 8% 5% 3 4 5% 9%	3594
	11th to 20th	Day	12% 17% 6% 22% 15% 7% 5% 3 4 3 6%	3589
	21st to end	Day	11% 17% 7% 18% 8% 8% 6% 4 5% 5% 11%	3982
February	1st to 10th	Day	9% 14% 5% 13% 8% 6% 6% 3 5% 7% 24%	1740
	11th to 20th	Day	11% 14% 5% 12% 7% 6% 5% 4 6% 6% 24%	1870
	21st to end	Day	10% 14% 5% 10% 7% 6% 5% 4 6% 7% 27%	1610
March	1st to 10th	Day	12% 11% 3 8% 5% 4 3 3 6% 7% 38%	3118
	11th to 20th	Day	8% 13% 4 10% 7% 6% 5% 4 5% 6% 32%	3447
	21st to end	Day	14% 11% 7% 9% 5% 5% 5% 4 5% 6% 27%	3867
April	1st to 10th	Day	17% 11% 3 8% 5% 5% 5% 3 5% 7% 31%	2280
	11th to 20th	Day	18% 10% 3 7% 4 4 4 3 5% 6% 36%	2408
	21st to end	Day	15% 9% 3 9% 5% 5% 4 3 6% 7% 35%	2470
May	1st to 10th	Day	14% 8% 2 6% 4 5% 5% 4 5% 7% 40%	4108
	11th to 20th	Day	11% 7% 2 7% 5% 5% 6% 4 5% 7% 42%	4194
	21st to end	Day	12% 6% 2 5% 4 4 4 4 6% 9% 45%	5044
June	1st to 10th	Day	13% 5% 2 6% 4 5% 4 5% 6% 9% 42%	2850
	11th to 20th	Day	11% 5% 2 7% 4 5% 5% 5% 7% 9% 40%	2850
	21st to end	Day	14% 7% 3 5% 4 4 3 4 5% 9% 43%	2850
July	1st to 10th	Day	16% 7% 2 6% 4 3 4 3 5% 7% 44%	4641
	11th to 20th	Day	7% 5% 2 5% 4 4 4 3 6% 8% 52%	4440
	21st to end	Day	9% 5% 2 5% 3 4 3 3 6% 8% 52%	4814
August	1st to 10th	Day	7% 6% 2 6% 5% 5% 5% 5% 6% 9% 45%	4206
	11th to 20th	Day	11% 5% 2 6% 4 4 4 4 6% 8% 47%	4044
	21st to end	Day	11% 6% 2 7% 4 4 4 3 4 7% 48%	4479
September	1st to 10th	Day	14% 6% 2 6% 4 4 4 3 5% 8% 44%	2220
	11th to 20th	Day	12% 5% 2 6% 4 5% 4 5% 5% 8% 44%	2090
	21st to end	Day	15% 8% 2 7% 5% 4 3 3 5% 8% 39%	2090
October	1st to 10th	Day	18% 9% 3 7% 4 3 5% 4 5% 8% 34%	2053
	11th to 20th	Day	20% 15% 4 10% 5% 5% 5% 4 5% 6% 21%	1826
	21st to end	Day	23% 15% 3 8% 5% 5% 5% 4 6% 7% 19%	1881
November	1st to 10th	Day	17% 14% 4 10% 5% 6% 6% 4 5% 8% 23%	1762
	11th to 20th	Day	14% 18% 6% 12% 7% 6% 5% 4 5% 5% 18%	1746
	21st to end	Day	20% 20% 9% 12% 6% 5% 5% 3 4 4 12%	1571
December	1st to 10th	Day	13% 25% 8% 15% 8% 5% 5% 4 4 4 9%	2280
	11th to 20th	Day	14% 19% 7% 18% 10% 7% 5% 3 4 4 9%	2621
	21st to end	Day	23% 20% 9% 16% 6% 4 5% 3 3 3 8%	3476
January	1st to 10th	Night	11% 14% 7% 23% 8% 6% 6% 4 5% 5% 12%	6368
	11th to 20th	Night	11% 17% 7% 20% 13% 7% 5% 3 4 3 9%	6316
	21st to end	Night	10% 16% 6% 15% 8% 7% 6% 4 5% 6% 15%	6996
February	1st to 10th	Night	10% 16% 5% 11% 9% 7% 5% 5% 5% 5% 22%	2658
	11th to 20th	Night	10% 14% 5% 14% 7% 6% 4 3 6% 6% 24%	2415
	21st to end	Night	14% 14% 5% 10% 8% 6% 5% 4 6% 6% 24%	1939
March	1st to 10th	Night	15% 11% 3 6% 4 3 3 2 4 7% 41%	3722
	11th to 20th	Night	9% 12% 4 9% 5% 4 5% 3 5% 7% 37%	3511
	21st to end	Night	14% 9% 6% 9% 5% 4 5% 3 6% 6% 32%	3792
April	1st to 10th	Night	19% 11% 3 7% 6% 5% 5% 4 5% 6% 29%	1900
	11th to 20th	Night	19% 9% 2 7% 5% 4 5% 3 4 5% 36%	1720
	21st to end	Night	17% 9% 2 8% 5% 4 5% 3 5% 6% 35%	1710
May	1st to 10th	Night	16% 8% 3 8% 5% 5% 4 4 5% 5% 37%	2833
	11th to 20th	Night	12% 8% 3 8% 6% 5% 4 4 6% 6% 39%	2701
	21st to end	Night	16% 6% 3 5% 4 3 3 3 5% 8% 42%	2541
June	1st to 10th	Night	13% 7% 2 6% 5% 5% 4 4 6% 9% 39%	1330
	11th to 20th	Night	11% 5% 2 6% 6% 4 5% 4 8% 8% 42%	1330
	21st to end	Night	14% 7% 2 5% 5% 4 4 4 5% 6% 44%	1330
July	1st to 10th	Night	13% 5% 2 6% 5% 5% 4 4 5% 8% 43%	2325
	11th to 20th	Night	8% 5% 2 6% 5% 4 4 4 5% 7% 52%	2530
	21st to end	Night	9% 6% 2 4 4 4 4 4 5% 8% 50%	2750
August	1st to 10th	Night	9% 6% 3 6% 5% 5% 4 4 5% 8% 44%	2724
	11th to 20th	Night	13% 5% 2 5% 3 3 3 3 5% 9% 49%	2785
	21st to end	Night	10% 5% 2 5% 4 3 4 3 5% 6% 52%	3174
September	1st to 10th	Night	13% 7% 2 6% 4 4 3 4 5% 6% 47%	1939
	11th to 20th	Night	15% 5% 2 5% 4 4 4 3 6% 8% 43%	2090
	21st to end	Night	17% 8% 3 7% 4 3 4 4 6% 7% 38%	2090
October	1st to 10th	Night	19% 8% 2 7% 5% 4 4 4 4 6% 38%	2126
	11th to 20th	Night	22% 12% 3 8% 5% 5% 4 4 5% 6% 25%	2351
	21st to end	Night	25% 14% 3 9% 6% 5% 4 4 4 5% 21%	2717
November	1st to 10th	Night	17% 15% 4 9% 6% 4 4 3 5% 8% 26%	2536
	11th to 20th	Night	15% 18% 5% 13% 7% 5% 5% 4 4 6% 18%	2651
	21st to end	Night	20% 21% 8% 12% 6% 4 5% 3 4 4 13%	2825
December	1st to 10th	Night	13% 21% 8% 17% 9% 5% 4 3 5% 5% 10%	4910
	11th to 20th	Night	13% 20% 7% 20% 8% 5% 5% 3 3 4 11%	5586
	21st to end	Night	24% 22% 10% 13% 6% 5% 4 2 3 3 8%	7502

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	56% 31% 6% 4 1 2	3595
	11th to 20th	Day	63% 28% 5% 3 1	3620
	21st to end	Day	56% 30% 8% 4 2	3982
February	1st to 10th	Day	22% 62% 6% 7% 3	1740
	11th to 20th	Day	25% 61% 4 5% 4	1879
	21st to end	Day	20% 64% 4 8% 4	1610
March	1st to 10th	Day	28% 39% 10% 14% 7% 1	3120
	11th to 20th	Day	35% 39% 7% 14% 4 1	3447
	21st to end	Day	37% 40% 6% 10% 7% 1	3867
April	1st to 10th	Day	20% 65% 3 8% 4	2280
	11th to 20th	Day	17% 65% 3 7% 6% 1	2408
	21st to end	Day	17% 65% 3 8% 6% 1	2470
May	1st to 10th	Day	28% 39% 4 16% 11% 1	4120
	11th to 20th	Day	27% 40% 6% 21% 7%	4198
	21st to end	Day	23% 39% 8% 15% 14% 1	5044
June	1st to 10th	Day	15% 65% 4 10% 6% 1	2850
	11th to 20th	Day	16% 65% 5% 8% 5% 1	2850
	21st to end	Day	14% 64% 5% 11% 5% 1	2850
July	1st to 10th	Day	30% 37% 11% 15% 7% 1	4570
	11th to 20th	Day	17% 38% 12% 27% 6%	4365
	21st to end	Day	18% 36% 7% 26% 13%	4662
August	1st to 10th	Day	19% 40% 10% 22% 8%	4191
	11th to 20th	Day	25% 39% 10% 20% 6%	4083
	21st to end	Day	25% 39% 12% 21% 4	4478
September	1st to 10th	Day	17% 61% 6% 12% 4	2220
	11th to 20th	Day	14% 60% 5% 15% 6%	2090
	21st to end	Day	18% 60% 7% 11% 4	2090
October	1st to 10th	Day	18% 38% 9% 23% 12%	3417
	11th to 20th	Day	30% 38% 7% 18% 6%	3016
	21st to end	Day	37% 39% 8% 13% 3	3081
November	1st to 10th	Day	28% 56% 5% 9% 2	1762
	11th to 20th	Day	31% 57% 6% 5% 2	1746
	21st to end	Day	34% 58% 4 3 1	1571
December	1st to 10th	Day	48% 39% 9% 4 1	2280
	11th to 20th	Day	53% 34% 7% 5% 1	2621
	21st to end	Day	62% 27% 3 5% 3	3476
January	1st to 10th	Night	52% 29% 8% 6% 4	6368
	11th to 20th	Night	61% 28% 6% 3 1	6360
	21st to end	Night	51% 30% 9% 8% 1	6996
February	1st to 10th	Night	23% 63% 4 6% 4	2658
	11th to 20th	Night	24% 61% 4 9% 2	2417
	21st to end	Night	21% 63% 5% 6% 5%	1939
March	1st to 10th	Night	27% 39% 12% 15% 6%	3733
	11th to 20th	Night	29% 39% 10% 15% 6% 1	3512
	21st to end	Night	34% 40% 8% 13% 5% 1	3792
April	1st to 10th	Night	22% 65% 2 7% 4	1900
	11th to 20th	Night	19% 65% 2 9% 4 2	1720
	21st to end	Night	19% 65% 3 7% 6% 1	1710
May	1st to 10th	Night	31% 40% 5% 14% 8% 1	2840
	11th to 20th	Night	27% 40% 4 20% 9%	2702
	21st to end	Night	28% 39% 10% 10% 9% 4	2542
June	1st to 10th	Night	15% 64% 4 9% 7%	1330
	11th to 20th	Night	16% 66% 3 9% 5% 2	1330
	21st to end	Night	15% 64% 4 11% 5% 2	1330
July	1st to 10th	Night	29% 37% 11% 13% 9% 1	2287
	11th to 20th	Night	19% 37% 12% 21% 11%	2482
	21st to end	Night	20% 36% 10% 17% 16%	2662
August	1st to 10th	Night	24% 40% 9% 17% 9%	2715
	11th to 20th	Night	24% 38% 9% 21% 7% 1	2812
	21st to end	Night	20% 38% 9% 23% 9%	3174
September	1st to 10th	Night	15% 61% 5% 12% 6%	1939
	11th to 20th	Night	14% 60% 6% 13% 6%	2090
	21st to end	Night	17% 60% 7% 12% 4	2090
October	1st to 10th	Night	23% 39% 8% 22% 9%	3542
	11th to 20th	Night	23% 38% 13% 16% 10%	3900
	21st to end	Night	33% 39% 10% 15% 3	4467
November	1st to 10th	Night	29% 56% 5% 8% 2	2536
	11th to 20th	Night	28% 58% 6% 6% 3	2651
	21st to end	Night	34% 57% 4 4 1	2825
December	1st to 10th	Night	46% 39% 8% 5% 1	4910
	11th to 20th	Night	52% 33% 6% 5% 2	5585
	21st to end	Night	62% 28% 4 5% 2	7502

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	18% 10% 34% 29% 8% 1	295
	11th to 20th	Day	22% 10% 31% 29% 7% 1	300
	21st to end	Day	23% 6% 25% 29% 15% 1	330
February	1st to 10th	Day	17% 11% 35% 26% 9% 1	300
	11th to 20th	Day	16% 8% 42% 24% 9% 1	300
	21st to end	Day	17% 12% 35% 30% 7%	237
March	1st to 10th	Day	15% 8% 32% 30% 14%	270
	11th to 20th	Day	16% 9% 29% 32% 12% 2	440
	21st to end	Day	24% 7% 26% 31% 10% 2	506
April	1st to 10th	Day	22% 7% 25% 35% 9% 2	460
	11th to 20th	Day	24% 6% 28% 27% 12% 2	452
	21st to end	Day	20% 5% 30% 30% 13% 3	460
May	1st to 10th	Day	22% 2 27% 30% 16% 3	463
	11th to 20th	Day	16% 3 18% 39% 19% 5%	548
	21st to end	Day	14% 2 18% 38% 22% 6%	734
June	1st to 10th	Day	12% 2 22% 38% 23% 4	680
	11th to 20th	Day	13% 2 19% 40% 22% 5%	680
	21st to end	Day	18% 4 14% 37% 23% 4	680
July	1st to 10th	Day	9% 1 13% 40% 28% 8%	671
	11th to 20th	Day	10% 2 14% 35% 31% 8%	668
	21st to end	Day	12% 2 13% 33% 31% 9%	739
August	1st to 10th	Day	12% 1 12% 35% 31% 10%	550
	11th to 20th	Day	10% 3 9% 30% 33% 14%	479
	21st to end	Day	14% 4 13% 35% 27% 8%	539
September	1st to 10th	Day	16% 3 16% 30% 26% 9%	490
	11th to 20th	Day	13% 3 14% 29% 29% 12%	490
	21st to end	Day	19% 5% 17% 30% 23% 6%	490
October	1st to 10th	Day	21% 7% 25% 24% 17% 6%	490
	11th to 20th	Day	24% 9% 25% 28% 13% 1	416
	21st to end	Day	32% 6% 22% 29% 9% 2	330
November	1st to 10th	Day	20% 12% 27% 28% 12% 2	300
	11th to 20th	Day	22% 13% 33% 23% 9% 1	273
	21st to end	Day	27% 14% 36% 21% 3	200
December	1st to 10th	Day	23% 12% 38% 19% 8% 1	200
	11th to 20th	Day	21% 17% 33% 21% 8% 1	200
	21st to end	Day	27% 15% 34% 18% 5% 1	220
January	1st to 10th	Night	22% 13% 33% 26% 6% 1	1000
	11th to 20th	Night	23% 12% 33% 24% 9%	1000
	21st to end	Night	18% 9% 33% 30% 8% 1	1100
February	1st to 10th	Night	16% 11% 37% 28% 8% 1	858
	11th to 20th	Night	18% 10% 35% 27% 10%	783
	21st to end	Night	19% 8% 35% 30% 8%	647
March	1st to 10th	Night	17% 6% 34% 31% 10% 1	760
	11th to 20th	Night	17% 9% 32% 33% 9% 1	760
	21st to end	Night	19% 7% 27% 34% 13% 1	823
April	1st to 10th	Night	24% 6% 26% 34% 10% 1	570
	11th to 20th	Night	23% 5% 23% 34% 12% 2	563
	21st to end	Night	22% 3 26% 34% 15% 1	570
May	1st to 10th	Night	18% 2 21% 37% 19% 2	570
	11th to 20th	Night	19% 4 14% 40% 21% 2	561
	21st to end	Night	15% 1 19% 34% 26% 4	499
June	1st to 10th	Night	14% 3 18% 38% 25% 2	380
	11th to 20th	Night	12% 2 18% 38% 25% 4	380
	21st to end	Night	17% 3 13% 38% 25% 3	380
July	1st to 10th	Night	11% 2 12% 41% 31% 4	430
	11th to 20th	Night	7% 3 12% 38% 31% 9%	552
	21st to end	Night	11% 2 11% 40% 30% 5%	624
August	1st to 10th	Night	12% 3 12% 40% 28% 5%	567
	11th to 20th	Night	10% 2 16% 31% 31% 10%	564
	21st to end	Night	15% 3 13% 39% 27% 4	627
September	1st to 10th	Night	16% 3 18% 29% 27% 7%	609
	11th to 20th	Night	15% 4 17% 31% 25% 8%	760
	21st to end	Night	21% 4 17% 28% 23% 7%	760
October	1st to 10th	Night	22% 5% 21% 31% 17% 2	760
	11th to 20th	Night	28% 9% 24% 30% 8% 1	760
	21st to end	Night	33% 9% 22% 29% 6% 1	836
November	1st to 10th	Night	24% 11% 28% 26% 10% 1	780
	11th to 20th	Night	26% 14% 31% 22% 7% 1	800
	21st to end	Night	31% 14% 30% 20% 5%	825
December	1st to 10th	Night	22% 16% 35% 20% 6% 1	1000
	11th to 20th	Night	25% 17% 34% 17% 6% 1	1000
	21st to end	Night	33% 11% 30% 19% 6% 1	1100

Page generated at 2025-02-22 06:51:38. Version ac07

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