Loeber/Elswick Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Loeber/Elswick Observatory clear sky chart from 2005-11-06 to 2024-12-02.

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	12% 8% 3 6% 4 4 4 4 5% 7% 43%	101446
	Night	13% 8% 3 6% 4 3 4 3 5% 6% 45%	98284
Transparency	Day	39% 5% 11% 25% 17% 3	105084
	Night	39% 4 11% 25% 18% 3	102786
Seeing	Day	18% 12% 28% 25% 14% 4	15706
	Night	18% 12% 30% 28% 12% 1	25548

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% 14% 4 9% 4 4 5% 3 5% 5% 35%	2629
	11th to 20th	Day	12% 12% 4 8% 5% 5% 4 3 4 6% 37%	2850
	21st to end	Day	20% 13% 6% 7% 3 3 3 3 4 5% 33%	3135
February	1st to 10th	Day	13% 14% 4 10% 5% 3 4 3 5% 5% 33%	1710
	11th to 20th	Day	16% 10% 2 6% 4 4 4 4 4 5% 40%	1744
	21st to end	Day	16% 10% 3 6% 4 4 3 4 5% 6% 38%	1570
March	1st to 10th	Day	19% 11% 3 5% 3 3 3 3 3 4 43%	3367
	11th to 20th	Day	13% 8% 2 5% 3 3 3 2 5% 6% 51%	3480
	21st to end	Day	16% 11% 3 8% 5% 5% 5% 4 5% 7% 32%	3895
April	1st to 10th	Day	12% 8% 2 6% 5% 3 4 4 4 7% 44%	2280
	11th to 20th	Day	17% 8% 2 5% 4 4 3 4 5% 6% 41%	2254
	21st to end	Day	20% 9% 3 8% 5% 4 4 3 5% 5% 35%	2280
May	1st to 10th	Day	15% 9% 3 7% 5% 4 5% 4 6% 9% 33%	3914
	11th to 20th	Day	18% 8% 2 7% 4 4 4 3 5% 6% 39%	4262
	21st to end	Day	11% 7% 3 7% 5% 5% 5% 4 6% 7% 43%	4824
June	1st to 10th	Day	9% 5% 2 6% 3 5% 4 4 8% 9% 44%	2660
	11th to 20th	Day	7% 5% 1 5% 4 4 5% 4 7% 10% 48%	2660
	21st to end	Day	6% 3 1 5% 4 4 5% 5% 7% 9% 51%	2660
July	1st to 10th	Day	13% 6% 2 6% 4 4 4 4 6% 9% 41%	4440
	11th to 20th	Day	4 4 2 6% 4 5% 5% 4 7% 11% 48%	4260
	21st to end	Day	7% 5% 2 6% 5% 5% 6% 5% 8% 11% 40%	4465
August	1st to 10th	Day	5% 4 1 4 4 4 5% 4 7% 11% 51%	4104
	11th to 20th	Day	12% 6% 2 6% 4 5% 4 4 5% 8% 45%	3854
	21st to end	Day	7% 4 2 4 4 4 4 4 6% 9% 52%	4180
September	1st to 10th	Day	11% 5% 2 5% 3 4 4 4 5% 8% 50%	2280
	11th to 20th	Day	12% 4 2 5% 4 4 4 3 6% 6% 51%	2280
	21st to end	Day	9% 5% 2 4 4 4 4 3 5% 8% 53%	2005
October	1st to 10th	Day	10% 5% 2 5% 4 3 3 3 4 5% 55%	1900
	11th to 20th	Day	16% 6% 2 4 2 2 2 2 4 5% 53%	1900
	21st to end	Day	18% 8% 2 5% 4 3 2 3 3 5% 47%	2090
November	1st to 10th	Day	12% 7% 2 5% 3 3 2 2 5% 5% 54%	1861
	11th to 20th	Day	15% 8% 3 5% 3 3 3 3 4 6% 47%	1800
	21st to end	Day	17% 11% 3 5% 2 3 2 3 4 6% 45%	1624
December	1st to 10th	Day	14% 11% 3 7% 4 3 3 4 4 6% 42%	1528
	11th to 20th	Day	13% 10% 5% 6% 5% 4 3 3 4 6% 41%	1918
	21st to end	Day	18% 16% 4 10% 5% 4 4 4 4 5% 26%	2783
January	1st to 10th	Night	12% 11% 7% 10% 5% 4 4 3 4 4 36%	4323
	11th to 20th	Night	14% 10% 4 12% 6% 6% 6% 3 4 4 31%	4120
	21st to end	Night	22% 15% 5% 7% 4 3 3 2 3 4 32%	4532
February	1st to 10th	Night	14% 12% 3 8% 4 4 4 3 5% 5% 36%	2470
	11th to 20th	Night	14% 9% 3 8% 5% 3 3 3 4 6% 41%	2323
	21st to end	Night	16% 11% 3 7% 5% 3 3 3 5% 4 40%	1884
March	1st to 10th	Night	20% 11% 2 4 3 3 2 2 4 4 45%	3515
	11th to 20th	Night	14% 7% 2 5% 3 2 3 3 4 7% 50%	3480
	21st to end	Night	18% 11% 3 8% 5% 4 5% 3 5% 6% 31%	3735
April	1st to 10th	Night	12% 7% 3 6% 3 3 3 3 5% 6% 50%	1900
	11th to 20th	Night	15% 9% 2 5% 3 3 3 3 5% 6% 47%	1875
	21st to end	Night	19% 6% 3 7% 4 4 4 4 4 8% 39%	1900
May	1st to 10th	Night	15% 8% 3 6% 4 3 4 3 6% 8% 41%	2983
	11th to 20th	Night	13% 8% 2 7% 5% 4 4 3 5% 8% 42%	2639
	21st to end	Night	10% 6% 2 7% 5% 4 5% 4 6% 9% 43%	2743
June	1st to 10th	Night	9% 3 2 5% 5% 4 4 3 6% 7% 50%	1520
	11th to 20th	Night	6% 3 2 4 4 3 5% 4 7% 11% 52%	1520
	21st to end	Night	4 3 1 4 3 3 3 4 7% 10% 58%	1520
July	1st to 10th	Night	12% 5% 2 6% 4 4 4 3 5% 9% 46%	2530
	11th to 20th	Night	4 3 2 5% 4 4 3 3 5% 10% 58%	2706
	21st to end	Night	6% 5% 2 6% 4 4 5% 5% 7% 9% 47%	3098
August	1st to 10th	Night	4 2 1 4 3 3 4 3 5% 9% 62%	2836
	11th to 20th	Night	10% 6% 2 6% 3 3 4 3 5% 8% 50%	2978
	21st to end	Night	5% 4 1 4 3 3 3 3 6% 9% 59%	3476
September	1st to 10th	Night	12% 4 1 5% 3 2 3 3 5% 6% 56%	1900
	11th to 20th	Night	9% 5% 2 5% 3 4 4 4 5% 7% 52%	1900
	21st to end	Night	9% 4 2 5% 4 3 3 3 4 6% 56%	2151
October	1st to 10th	Night	7% 4 1 5% 3 3 3 3 4 7% 61%	2280
	11th to 20th	Night	14% 6% 2 5% 3 3 3 2 4 5% 53%	2280
	21st to end	Night	18% 7% 2 4 3 3 3 2 4 4 49%	2508
November	1st to 10th	Night	11% 6% 2 5% 3 3 2 3 4 6% 56%	2435
	11th to 20th	Night	13% 6% 3 6% 4 3 3 3 4 6% 50%	2600
	21st to end	Night	17% 10% 3 5% 3 3 3 2 4 4 46%	2774
December	1st to 10th	Night	14% 12% 3 7% 4 4 3 4 6% 6% 38%	2687
	11th to 20th	Night	15% 11% 4 7% 4 3 4 3 4 5% 41%	3279
	21st to end	Night	16% 20% 6% 10% 5% 5% 4 3 4 4 25%	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	50% 4 9% 24% 12% 1	2630
	11th to 20th	Day	48% 5% 10% 23% 14%	2850
	21st to end	Day	54% 4 8% 17% 14% 3	3135
February	1st to 10th	Day	54% 3 9% 21% 12% 1	1710
	11th to 20th	Day	47% 3 11% 21% 15% 4	1753
	21st to end	Day	47% 3 8% 24% 14% 5%	1570
March	1st to 10th	Day	46% 3 7% 21% 18% 5%	3367
	11th to 20th	Day	36% 5% 9% 28% 17% 5%	3480
	21st to end	Day	50% 7% 14% 20% 8% 1	3895
April	1st to 10th	Day	39% 4 11% 25% 19% 2	2280
	11th to 20th	Day	43% 4 10% 24% 16% 3	2254
	21st to end	Day	51% 4 10% 20% 13% 1	2280
May	1st to 10th	Day	46% 7% 12% 22% 12% 1	3949
	11th to 20th	Day	45% 6% 10% 24% 13% 1	4266
	21st to end	Day	39% 6% 9% 26% 19% 1	4837
June	1st to 10th	Day	33% 7% 15% 27% 16% 2	2660
	11th to 20th	Day	30% 5% 13% 30% 18% 4	2660
	21st to end	Day	27% 6% 18% 30% 15% 5%	2660
July	1st to 10th	Day	39% 5% 12% 26% 15% 2	4371
	11th to 20th	Day	29% 5% 14% 33% 16% 2	4186
	21st to end	Day	35% 8% 18% 28% 9% 2	4325
August	1st to 10th	Day	27% 6% 17% 34% 16% 1	4090
	11th to 20th	Day	38% 5% 13% 27% 16% 1	3893
	21st to end	Day	29% 6% 14% 35% 14% 3	4179
September	1st to 10th	Day	34% 3 10% 27% 19% 5%	2280
	11th to 20th	Day	33% 3 9% 27% 25% 3	2280
	21st to end	Day	31% 5% 8% 29% 24% 3	2005
October	1st to 10th	Day	19% 2 5% 19% 42% 13%	3160
	11th to 20th	Day	23% 2 4 23% 37% 11%	3140
	21st to end	Day	33% 2 7% 28% 27% 2	3428
November	1st to 10th	Day	34% 2 12% 25% 22% 5%	1861
	11th to 20th	Day	39% 3 8% 23% 22% 5%	1800
	21st to end	Day	43% 3 8% 29% 16% 1	1624
December	1st to 10th	Day	44% 3 10% 30% 12% 1	1528
	11th to 20th	Day	46% 3 10% 23% 17% 2	1915
	21st to end	Day	60% 5% 10% 15% 9% 1	2783
January	1st to 10th	Night	52% 4 10% 23% 11% 1	4323
	11th to 20th	Night	57% 5% 8% 20% 9% 1	4120
	21st to end	Night	58% 4 8% 21% 9% 1	4532
February	1st to 10th	Night	51% 4 9% 20% 14% 2	2470
	11th to 20th	Night	45% 3 9% 23% 17% 3	2324
	21st to end	Night	48% 3 9% 20% 16% 4	1884
March	1st to 10th	Night	44% 3 9% 23% 17% 4	3515
	11th to 20th	Night	35% 4 10% 25% 22% 4	3480
	21st to end	Night	52% 7% 11% 23% 6% 1	3735
April	1st to 10th	Night	35% 4 12% 27% 19% 4	1900
	11th to 20th	Night	39% 3 10% 25% 17% 6%	1875
	21st to end	Night	46% 3 10% 24% 16% 1	1900
May	1st to 10th	Night	40% 7% 15% 21% 15% 2	3013
	11th to 20th	Night	41% 6% 12% 26% 13% 1	2640
	21st to end	Night	37% 7% 13% 24% 18% 1	2751
June	1st to 10th	Night	32% 5% 14% 28% 17% 3	1520
	11th to 20th	Night	26% 5% 12% 29% 24% 4	1520
	21st to end	Night	21% 6% 17% 29% 20% 7%	1520
July	1st to 10th	Night	37% 5% 11% 27% 17% 3	2490
	11th to 20th	Night	23% 4 11% 39% 20% 2	2657
	21st to end	Night	30% 8% 18% 30% 13% 1	2999
August	1st to 10th	Night	20% 5% 20% 32% 23% 1	2826
	11th to 20th	Night	34% 4 14% 28% 17% 3	3005
	21st to end	Night	22% 5% 16% 37% 16% 4	3476
September	1st to 10th	Night	30% 4 11% 25% 25% 6%	1900
	11th to 20th	Night	31% 4 10% 23% 27% 4	1900
	21st to end	Night	30% 4 8% 27% 28% 3	2151
October	1st to 10th	Night	15% 2 6% 21% 46% 11%	3800
	11th to 20th	Night	23% 2 6% 21% 33% 15%	3779
	21st to end	Night	34% 3 7% 27% 26% 3	4120
November	1st to 10th	Night	31% 3 11% 28% 21% 6%	2435
	11th to 20th	Night	37% 2 6% 25% 24% 5%	2600
	21st to end	Night	42% 3 9% 26% 18% 2	2774
December	1st to 10th	Night	47% 3 10% 24% 14% 1	2687
	11th to 20th	Night	47% 3 9% 26% 15% 1	3281
	21st to end	Night	63% 5% 9% 14% 8% 1	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% 23% 34% 16% 2	270
	11th to 20th	Day	36% 17% 37% 9% 1	270
	21st to end	Day	23% 26% 36% 12% 3	297
February	1st to 10th	Day	30% 21% 33% 15% 1	270
	11th to 20th	Day	31% 24% 29% 12% 3	270
	21st to end	Day	34% 20% 36% 10%	225
March	1st to 10th	Day	24% 25% 41% 10% 1	270
	11th to 20th	Day	32% 19% 35% 12% 1 1	270
	21st to end	Day	36% 23% 27% 13% 1	340
April	1st to 10th	Day	24% 16% 37% 19% 5% 1	460
	11th to 20th	Day	30% 17% 30% 17% 6% 1	452
	21st to end	Day	27% 15% 35% 19% 5%	460
May	1st to 10th	Day	21% 16% 35% 22% 6% 1	547
	11th to 20th	Day	21% 13% 27% 25% 11% 2	675
	21st to end	Day	13% 11% 31% 25% 14% 5%	734
June	1st to 10th	Day	9% 6% 25% 35% 19% 7%	680
	11th to 20th	Day	8% 5% 24% 40% 20% 3	680
	21st to end	Day	6% 7% 34% 34% 14% 4	680
July	1st to 10th	Day	13% 3 17% 29% 28% 9%	671
	11th to 20th	Day	5% 5% 21% 39% 26% 5%	668
	21st to end	Day	9% 4 17% 36% 27% 7%	739
August	1st to 10th	Day	10% 4 17% 38% 25% 5%	676
	11th to 20th	Day	10% 4 20% 36% 24% 6%	556
	21st to end	Day	9% 3 17% 31% 29% 11%	539
September	1st to 10th	Day	13% 4 15% 32% 28% 8%	490
	11th to 20th	Day	10% 2 21% 31% 26% 9%	490
	21st to end	Day	13% 10% 23% 32% 18% 4	357
October	1st to 10th	Day	13% 7% 34% 27% 14% 4	300
	11th to 20th	Day	22% 18% 34% 18% 8% 1	300
	21st to end	Day	33% 18% 31% 16% 2	330
November	1st to 10th	Day	18% 12% 41% 19% 7% 2	300
	11th to 20th	Day	28% 18% 30% 18% 5% 2	300
	21st to end	Day	29% 17% 30% 19% 4 1	300
December	1st to 10th	Day	19% 26% 32% 15% 7% 1	273
	11th to 20th	Day	27% 19% 36% 15% 3	270
	21st to end	Day	26% 27% 34% 12% 2	297
January	1st to 10th	Night	20% 19% 36% 21% 4	950
	11th to 20th	Night	25% 20% 34% 17% 3	950
	21st to end	Night	21% 18% 36% 23% 2	1045
February	1st to 10th	Night	22% 18% 38% 19% 3	950
	11th to 20th	Night	22% 19% 37% 20% 2	849
	21st to end	Night	28% 17% 36% 16% 3	628
March	1st to 10th	Night	21% 18% 37% 21% 3	632
	11th to 20th	Night	23% 13% 35% 25% 4	570
	21st to end	Night	28% 14% 36% 19% 3	627
April	1st to 10th	Night	17% 19% 35% 25% 4	570
	11th to 20th	Night	23% 13% 33% 26% 5%	563
	21st to end	Night	22% 11% 38% 23% 6%	570
May	1st to 10th	Night	17% 6% 37% 31% 8% 1	570
	11th to 20th	Night	16% 8% 28% 32% 14% 1	561
	21st to end	Night	13% 6% 27% 33% 20% 1	617
June	1st to 10th	Night	10% 4 19% 39% 25% 2	570
	11th to 20th	Night	7% 3 25% 45% 19% 1	570
	21st to end	Night	4 3 28% 46% 17% 2	570
July	1st to 10th	Night	11% 3 13% 34% 32% 6%	555
	11th to 20th	Night	3 4 16% 45% 30% 2	552
	21st to end	Night	6% 3 16% 41% 31% 3	624
August	1st to 10th	Night	7% 3 13% 42% 33% 2	567
	11th to 20th	Night	9% 2 14% 41% 31% 2	564
	21st to end	Night	7% 2 13% 39% 36% 3	627
September	1st to 10th	Night	13% 2 15% 38% 27% 5%	570
	11th to 20th	Night	11% 3 15% 39% 28% 4	570
	21st to end	Night	11% 6% 24% 33% 23% 3	692
October	1st to 10th	Night	9% 7% 27% 32% 22% 3	760
	11th to 20th	Night	16% 12% 35% 27% 9% 1	760
	21st to end	Night	23% 13% 32% 25% 6%	836
November	1st to 10th	Night	14% 13% 36% 28% 9%	780
	11th to 20th	Night	20% 16% 32% 26% 7%	800
	21st to end	Night	24% 14% 33% 23% 6%	974
December	1st to 10th	Night	23% 14% 35% 22% 5% 1	960
	11th to 20th	Night	24% 14% 34% 24% 4	950
	21st to end	Night	27% 19% 32% 20% 2	1045

Page generated at 2024-11-29 09:43:05. Version ac07

Copyright © 2024 Attilla Danko.