Wasat Star
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Wasat Star clear sky chart from 2005-11-06 to 2025-02-21.

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% 5% 2 5% 3 4 4 3 5% 7% 52%	109204
	Night	12% 5% 2 4 3 3 3 3 4 6% 56%	109629
Transparency	Day	31% 5% 10% 21% 22% 11%	113048
	Night	28% 5% 10% 21% 22% 13%	113912
Seeing	Day	12% 5% 20% 30% 25% 8%	15242
	Night	13% 5% 25% 39% 18% 1	25321

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	12% 8% 1 4 2 3 2 2 3 5% 57%	4077
	11th to 20th	Day	11% 6% 1 3 2 2 3 2 4 5% 60%	4080
	21st to end	Day	21% 5% 2 4 3 3 3 2 4 5% 48%	4872
February	1st to 10th	Day	14% 7% 2 5% 3 3 3 3 3 5% 53%	2000
	11th to 20th	Day	15% 5% 2 6% 3 2 3 3 4 6% 50%	1949
	21st to end	Day	15% 5% 2 4 3 3 3 3 4 5% 54%	1570
March	1st to 10th	Day	14% 8% 2 6% 4 3 3 3 5% 5% 47%	3315
	11th to 20th	Day	17% 7% 3 7% 4 5% 5% 3 5% 7% 38%	3480
	21st to end	Day	9% 6% 2 6% 3 4 4 4 6% 7% 48%	3814
April	1st to 10th	Day	11% 6% 2 5% 4 4 4 4 5% 6% 50%	2090
	11th to 20th	Day	15% 7% 2 5% 4 3 4 2 5% 5% 47%	2159
	21st to end	Day	13% 6% 2 4 4 4 4 3 4 5% 52%	2399
May	1st to 10th	Day	18% 8% 2 5% 4 4 4 4 5% 7% 39%	4082
	11th to 20th	Day	14% 7% 2 5% 4 4 4 3 5% 5% 46%	4082
	21st to end	Day	12% 5% 2 6% 4 6% 6% 4 7% 8% 40%	4477
June	1st to 10th	Day	6% 3 1 4 3 4 4 4 6% 8% 56%	2470
	11th to 20th	Day	5% 3 2 4 3 4 4 4 6% 9% 55%	2470
	21st to end	Day	8% 4 2 4 3 4 5% 5% 7% 9% 49%	2470
July	1st to 10th	Day	5% 3 1 5% 4 5% 5% 5% 7% 8% 52%	4120
	11th to 20th	Day	3 2 1 3 3 3 4 3 6% 10% 62%	4120
	21st to end	Day	7% 4 2 6% 4 5% 6% 5% 7% 10% 45%	4465
August	1st to 10th	Day	1 1 3 2 3 4 3 5% 7% 71%	4024
	11th to 20th	Day	4 2 1 3 3 3 3 3 6% 7% 65%	3726
	21st to end	Day	3 3 1 4 4 5% 5% 4 7% 9% 56%	4094
September	1st to 10th	Day	11% 5% 2 5% 4 4 4 4 5% 6% 50%	2090
	11th to 20th	Day	10% 5% 2 5% 5% 5% 4 3 5% 6% 48%	2090
	21st to end	Day	8% 3 1 5% 4 4 5% 4 5% 6% 55%	2090
October	1st to 10th	Day	5% 3 1 4 3 3 4 3 5% 6% 62%	2090
	11th to 20th	Day	11% 5% 1 4 3 3 3 2 3 5% 60%	1995
	21st to end	Day	13% 4 1 4 2 3 2 2 3 3 62%	2090
November	1st to 10th	Day	14% 7% 1 4 3 2 2 2 4 6% 53%	1935
	11th to 20th	Day	7% 5% 1 5% 3 3 3 3 4 7% 59%	1800
	21st to end	Day	14% 7% 3 5% 3 3 3 3 3 4 53%	1800
December	1st to 10th	Day	18% 7% 2 6% 4 3 3 2 4 4 46%	2940
	11th to 20th	Day	12% 7% 2 6% 4 4 4 3 5% 5% 46%	3391
	21st to end	Day	12% 5% 2 4 2 2 2 2 3 5% 62%	4488
January	1st to 10th	Night	15% 5% 2 4 2 2 2 2 3 5% 59%	5888
	11th to 20th	Night	10% 3 1 3 2 1 2 2 3 6% 69%	5900
	21st to end	Night	24% 6% 2 5% 3 2 2 2 3 5% 44%	6150
February	1st to 10th	Night	14% 6% 2 4 3 2 2 2 4 6% 55%	2400
	11th to 20th	Night	17% 5% 2 3 3 2 3 2 4 6% 53%	2338
	21st to end	Night	17% 5% 1 4 3 3 3 3 4 5% 52%	1884
March	1st to 10th	Night	12% 6% 2 5% 3 4 3 3 5% 6% 51%	3542
	11th to 20th	Night	16% 7% 2 6% 4 4 4 4 5% 5% 41%	3480
	21st to end	Night	10% 6% 2 6% 4 4 4 3 5% 6% 52%	3817
April	1st to 10th	Night	8% 6% 2 4 3 3 4 3 5% 6% 54%	2090
	11th to 20th	Night	15% 6% 2 5% 3 3 4 3 4 6% 50%	1966
	21st to end	Night	13% 5% 1 4 3 3 2 2 5% 7% 54%	1781
May	1st to 10th	Night	22% 8% 2 4 3 2 3 2 4 6% 44%	2823
	11th to 20th	Night	10% 6% 2 5% 3 3 4 3 5% 7% 52%	2823
	21st to end	Night	11% 5% 2 4 3 4 5% 4 5% 8% 48%	3090
June	1st to 10th	Night	4 3 1 3 3 3 4 4 6% 9% 61%	1710
	11th to 20th	Night	4 3 1 4 2 2 3 3 5% 9% 64%	1710
	21st to end	Night	5% 3 1 4 4 3 4 4 5% 8% 60%	1710
July	1st to 10th	Night	4 3 1 3 3 4 3 3 6% 8% 62%	2850
	11th to 20th	Night	2 2 1 2 2 2 3 3 5% 9% 68%	2850
	21st to end	Night	7% 5% 2 5% 4 4 4 3 7% 10% 51%	3098
August	1st to 10th	Night	1 1 2 1 2 2 2 5% 7% 76%	2897
	11th to 20th	Night	3 2 1 2 2 2 3 4 6% 9% 64%	3113
	21st to end	Night	3 3 1 3 2 3 3 4 7% 11% 59%	3570
September	1st to 10th	Night	9% 4 1 4 4 3 4 3 6% 7% 54%	2090
	11th to 20th	Night	10% 5% 2 5% 3 4 4 4 6% 8% 50%	2090
	21st to end	Night	7% 4 2 4 3 3 4 3 5% 7% 58%	2090
October	1st to 10th	Night	6% 3 1 3 3 2 2 2 4 7% 67%	2090
	11th to 20th	Night	12% 3 1 3 4 3 3 2 3 6% 60%	2166
	21st to end	Night	13% 4 1 4 2 2 3 2 4 4 61%	2508
November	1st to 10th	Night	12% 6% 2 4 2 2 2 2 4 5% 58%	2359
	11th to 20th	Night	7% 4 2 4 3 3 4 2 4 5% 61%	2600
	21st to end	Night	15% 5% 2 4 3 3 3 3 4 6% 52%	2600
December	1st to 10th	Night	18% 5% 2 4 3 3 4 4 5% 6% 47%	4250
	11th to 20th	Night	17% 8% 2 5% 3 3 2 3 3 4 50%	4816
	21st to end	Night	15% 5% 1 3 2 2 2 2 3 4 60%	6490

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	32% 3 4 23% 25% 13%	4078
	11th to 20th	Day	29% 2 5% 18% 27% 20%	4080
	21st to end	Day	40% 3 6% 10% 26% 15%	4872
February	1st to 10th	Day	35% 3 6% 15% 21% 20%	2000
	11th to 20th	Day	36% 3 7% 20% 19% 15%	1959
	21st to end	Day	35% 3 5% 15% 24% 18%	1570
March	1st to 10th	Day	38% 5% 7% 13% 21% 17%	3315
	11th to 20th	Day	46% 7% 10% 11% 17% 10%	3480
	21st to end	Day	32% 8% 11% 15% 22% 12%	3814
April	1st to 10th	Day	35% 5% 9% 18% 18% 16%	2090
	11th to 20th	Day	39% 5% 7% 15% 21% 12%	2159
	21st to end	Day	34% 5% 7% 21% 22% 11%	2399
May	1st to 10th	Day	43% 8% 11% 15% 16% 7%	4120
	11th to 20th	Day	38% 6% 8% 16% 24% 7%	4086
	21st to end	Day	36% 11% 14% 22% 12% 5%	4489
June	1st to 10th	Day	24% 8% 13% 29% 21% 5%	2470
	11th to 20th	Day	25% 6% 14% 27% 21% 7%	2470
	21st to end	Day	29% 8% 14% 23% 22% 5%	2470
July	1st to 10th	Day	27% 7% 17% 38% 10% 1	4056
	11th to 20th	Day	19% 6% 14% 36% 20% 4	4051
	21st to end	Day	29% 8% 17% 30% 15% 1	4325
August	1st to 10th	Day	12% 5% 11% 36% 34% 2	4010
	11th to 20th	Day	18% 5% 17% 40% 17% 3	3762
	21st to end	Day	22% 9% 19% 26% 20% 3	4093
September	1st to 10th	Day	34% 6% 9% 21% 19% 10%	2090
	11th to 20th	Day	35% 7% 12% 19% 21% 6%	2090
	21st to end	Day	27% 7% 10% 21% 22% 13%	2090
October	1st to 10th	Day	14% 3 7% 12% 27% 37%	3480
	11th to 20th	Day	21% 3 5% 20% 27% 23%	3300
	21st to end	Day	23% 3 4 18% 38% 14%	3428
November	1st to 10th	Day	33% 5% 8% 20% 22% 12%	1935
	11th to 20th	Day	28% 4 9% 19% 22% 19%	1800
	21st to end	Day	36% 3 5% 19% 21% 16%	1800
December	1st to 10th	Day	43% 3 5% 17% 21% 10%	2940
	11th to 20th	Day	39% 4 7% 10% 24% 14%	3389
	21st to end	Day	28% 3 4 18% 26% 21%	4488
January	1st to 10th	Night	32% 2 5% 21% 27% 13%	5888
	11th to 20th	Night	21% 2 4 19% 31% 24%	5900
	21st to end	Night	44% 4 4 10% 21% 17%	6150
February	1st to 10th	Night	34% 3 8% 13% 22% 20%	2400
	11th to 20th	Night	35% 3 7% 19% 20% 16%	2338
	21st to end	Night	34% 3 7% 13% 21% 21%	1884
March	1st to 10th	Night	32% 6% 8% 16% 25% 13%	3542
	11th to 20th	Night	43% 8% 9% 14% 16% 10%	3480
	21st to end	Night	32% 6% 11% 18% 22% 10%	3817
April	1st to 10th	Night	31% 6% 9% 20% 18% 17%	2090
	11th to 20th	Night	35% 5% 9% 15% 19% 17%	1966
	21st to end	Night	32% 5% 9% 21% 22% 10%	1781
May	1st to 10th	Night	39% 7% 10% 20% 15% 9%	2850
	11th to 20th	Night	30% 7% 12% 23% 18% 9%	2824
	21st to end	Night	32% 9% 13% 28% 12% 5%	3099
June	1st to 10th	Night	18% 8% 16% 32% 22% 4	1710
	11th to 20th	Night	18% 6% 16% 30% 22% 7%	1710
	21st to end	Night	22% 7% 13% 29% 24% 5%	1710
July	1st to 10th	Night	21% 6% 22% 41% 9% 1	2805
	11th to 20th	Night	14% 5% 20% 39% 20% 3	2796
	21st to end	Night	27% 6% 20% 34% 12% 1	2999
August	1st to 10th	Night	9% 4 14% 37% 35% 2	2887
	11th to 20th	Night	16% 5% 24% 38% 15% 2	3143
	21st to end	Night	18% 10% 22% 27% 20% 3	3570
September	1st to 10th	Night	28% 7% 13% 23% 19% 11%	2090
	11th to 20th	Night	31% 8% 15% 23% 17% 6%	2090
	21st to end	Night	24% 5% 12% 22% 21% 15%	2090
October	1st to 10th	Night	11% 3 7% 16% 22% 41%	3480
	11th to 20th	Night	19% 3 8% 17% 31% 21%	3587
	21st to end	Night	22% 3 5% 20% 35% 16%	4120
November	1st to 10th	Night	29% 4 9% 19% 25% 15%	2359
	11th to 20th	Night	26% 4 7% 21% 22% 19%	2600
	21st to end	Night	35% 4 7% 17% 22% 15%	2600
December	1st to 10th	Night	39% 3 7% 18% 21% 12%	4250
	11th to 20th	Night	39% 3 6% 11% 24% 17%	4817
	21st to end	Night	30% 2 4 17% 28% 18%	6490

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% 10% 34% 29% 9% 1	300
	11th to 20th	Day	19% 11% 30% 29% 9% 2	300
	21st to end	Day	19% 9% 37% 25% 9% 1	330
February	1st to 10th	Day	20% 15% 32% 24% 9% 1	300
	11th to 20th	Day	19% 13% 38% 25% 6%	300
	21st to end	Day	22% 11% 40% 23% 4	225
March	1st to 10th	Day	22% 10% 36% 25% 7%	270
	11th to 20th	Day	16% 10% 45% 21% 8%	270
	21st to end	Day	12% 12% 43% 25% 8%	297
April	1st to 10th	Day	17% 13% 39% 24% 6% 1	270
	11th to 20th	Day	17% 13% 39% 25% 7%	357
	21st to end	Day	17% 12% 38% 24% 9%	579
May	1st to 10th	Day	17% 7% 34% 31% 11%	653
	11th to 20th	Day	18% 3 29% 36% 13% 2	675
	21st to end	Day	16% 3 25% 38% 16% 3	734
June	1st to 10th	Day	8% 2 13% 40% 30% 8%	680
	11th to 20th	Day	5% 2 15% 44% 29% 5%	680
	21st to end	Day	8% 1 9% 35% 38% 10%	680
July	1st to 10th	Day	8% 1 5% 31% 39% 15%	671
	11th to 20th	Day	4 4 28% 52% 13%	668
	21st to end	Day	4 1 4 28% 47% 16%	739
August	1st to 10th	Day	3 3 29% 47% 19%	635
	11th to 20th	Day	10% 3 30% 41% 16%	477
	21st to end	Day	5% 1 4 25% 41% 24%	492
September	1st to 10th	Day	12% 3 18% 41% 26%	300
	11th to 20th	Day	8% 3 20% 42% 26%	300
	21st to end	Day	12% 1 4 30% 33% 20%	300
October	1st to 10th	Day	4 1 10% 29% 43% 13%	300
	11th to 20th	Day	11% 2 22% 35% 24% 6%	300
	21st to end	Day	18% 7% 23% 28% 19% 6%	330
November	1st to 10th	Day	21% 4 21% 32% 18% 4	300
	11th to 20th	Day	13% 9% 22% 31% 18% 7%	300
	21st to end	Day	21% 9% 32% 22% 12% 3	300
December	1st to 10th	Day	16% 6% 27% 31% 14% 5%	300
	11th to 20th	Day	16% 9% 33% 26% 13% 2	300
	21st to end	Day	18% 7% 30% 28% 15% 2	330
January	1st to 10th	Night	17% 7% 31% 36% 9%	1000
	11th to 20th	Night	15% 9% 29% 38% 8%	1000
	21st to end	Night	19% 8% 30% 35% 7%	955
February	1st to 10th	Night	19% 8% 33% 34% 7%	800
	11th to 20th	Night	20% 10% 35% 30% 5%	784
	21st to end	Night	21% 10% 41% 26% 2	628
March	1st to 10th	Night	18% 10% 33% 36% 3	646
	11th to 20th	Night	16% 8% 35% 33% 7%	570
	21st to end	Night	12% 10% 43% 31% 5%	627
April	1st to 10th	Night	11% 7% 46% 32% 3	570
	11th to 20th	Night	19% 7% 43% 27% 3	563
	21st to end	Night	14% 6% 46% 27% 6%	570
May	1st to 10th	Night	15% 6% 41% 32% 5%	570
	11th to 20th	Night	12% 3 33% 40% 11% 1	561
	21st to end	Night	13% 4 31% 38% 13% 1	617
June	1st to 10th	Night	5% 1 16% 52% 24% 1	570
	11th to 20th	Night	5% 1 22% 54% 17% 1	570
	21st to end	Night	5% 1 13% 49% 29% 3	570
July	1st to 10th	Night	8% 1 6% 44% 37% 4	555
	11th to 20th	Night	4 6% 47% 39% 3	552
	21st to end	Night	4 5% 43% 44% 3	624
August	1st to 10th	Night	2 3 44% 49% 2	567
	11th to 20th	Night	7% 1 2 46% 40% 4	564
	21st to end	Night	6% 3 41% 45% 5%	627
September	1st to 10th	Night	10% 1 6% 38% 41% 4	570
	11th to 20th	Night	12% 5% 38% 43% 3	570
	21st to end	Night	8% 1 8% 40% 40% 3	570
October	1st to 10th	Night	7% 2 11% 48% 31% 2	570
	11th to 20th	Night	12% 3 20% 44% 19% 1	646
	21st to end	Night	15% 6% 25% 33% 20% 2	836
November	1st to 10th	Night	14% 4 20% 43% 18% 1	799
	11th to 20th	Night	10% 6% 24% 42% 16% 1	1000
	21st to end	Night	18% 7% 26% 35% 13% 1	1000
December	1st to 10th	Night	15% 6% 26% 44% 10%	1000
	11th to 20th	Night	21% 6% 26% 38% 8%	1000
	21st to end	Night	15% 8% 29% 38% 10%	1100

Page generated at 2025-02-18 02:26:29. Version ac07

Copyright © 2025 Attilla Danko.