Honea-Egypt Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Honea-Egypt Observatory clear sky chart from 2005-11-06 to 2025-12-03.

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% 6% 2 6% 4 4 5% 4 6% 8% 41%	126906
	Night	14% 7% 2 5% 3 3 3 3 5% 7% 46%	124037
Transparency	Day	40% 5% 11% 20% 17% 7%	130568
	Night	38% 4 11% 20% 18% 9%	128438
Seeing	Day	15% 9% 22% 27% 21% 7%	16303
	Night	17% 8% 25% 32% 16% 2	26140

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	19% 10% 3 5% 3 3 3 2 3 5% 43%	4077
	11th to 20th	Day	16% 6% 2 5% 4 3 3 2 3 5% 50%	4080
	21st to end	Day	30% 9% 2 5% 2 2 2 2 4 6% 36%	4488
February	1st to 10th	Day	23% 8% 3 6% 4 3 3 3 4 6% 37%	1900
	11th to 20th	Day	22% 9% 3 6% 5% 3 3 2 3 5% 39%	1949
	21st to end	Day	21% 9% 3 6% 4 3 3 2 4 5% 41%	1811
March	1st to 10th	Day	17% 8% 3 7% 5% 5% 4 3 5% 6% 37%	4936
	11th to 20th	Day	15% 6% 2 6% 4 3 4 3 5% 6% 47%	4980
	21st to end	Day	18% 8% 2 6% 4 4 4 4 5% 5% 40%	5462
April	1st to 10th	Day	17% 8% 3 8% 5% 4 4 4 4 6% 38%	2200
	11th to 20th	Day	17% 7% 3 6% 5% 5% 4 3 5% 6% 39%	2322
	21st to end	Day	13% 8% 2 6% 5% 4 4 4 6% 7% 41%	2400
May	1st to 10th	Day	20% 7% 3 7% 5% 5% 5% 4 6% 7% 31%	5622
	11th to 20th	Day	11% 6% 2 7% 4 5% 5% 4 6% 8% 43%	5862
	21st to end	Day	10% 7% 3 7% 5% 5% 6% 5% 8% 10% 34%	6434
June	1st to 10th	Day	7% 5% 2 6% 5% 6% 7% 5% 8% 9% 42%	2600
	11th to 20th	Day	6% 4 1 5% 5% 5% 7% 5% 9% 11% 42%	2600
	21st to end	Day	7% 5% 2 8% 7% 7% 8% 6% 9% 9% 31%	2600
July	1st to 10th	Day	8% 5% 2 7% 6% 6% 7% 6% 8% 11% 34%	5900
	11th to 20th	Day	5% 5% 2 6% 5% 6% 7% 5% 9% 14% 34%	5900
	21st to end	Day	10% 7% 3 8% 5% 5% 5% 5% 7% 10% 36%	6422
August	1st to 10th	Day	2 2 1 3 3 4 4 4 7% 10% 61%	4234
	11th to 20th	Day	3 2 1 4 4 5% 7% 5% 10% 13% 47%	4044
	21st to end	Day	6% 5% 2 8% 5% 6% 6% 5% 7% 9% 40%	4199
September	1st to 10th	Day	7% 6% 2 6% 6% 5% 5% 5% 7% 9% 42%	2200
	11th to 20th	Day	12% 6% 2 7% 6% 6% 5% 4 5% 7% 40%	2200
	21st to end	Day	8% 4 2 6% 4 5% 5% 4 6% 7% 48%	2200
October	1st to 10th	Day	7% 3 2 4 4 3 4 3 5% 6% 59%	2089
	11th to 20th	Day	10% 5% 2 6% 3 4 4 3 4 6% 53%	2000
	21st to end	Day	13% 5% 2 4 3 3 3 3 5% 4 54%	2200
November	1st to 10th	Day	11% 6% 2 6% 4 3 4 4 6% 7% 48%	2058
	11th to 20th	Day	10% 7% 2 5% 4 3 3 4 6% 5% 50%	2100
	21st to end	Day	17% 6% 3 5% 5% 4 4 3 4 5% 43%	2000
December	1st to 10th	Day	23% 8% 2 5% 4 3 3 3 4 6% 39%	2958
	11th to 20th	Day	14% 9% 3 7% 4 3 3 3 4 6% 42%	3391
	21st to end	Day	17% 7% 2 6% 4 3 3 2 4 5% 47%	4488
January	1st to 10th	Night	19% 8% 2 5% 2 3 3 2 4 5% 47%	5888
	11th to 20th	Night	15% 7% 2 4 3 3 2 2 3 5% 53%	5900
	21st to end	Night	30% 9% 2 5% 3 2 3 2 4 5% 35%	6490
February	1st to 10th	Night	21% 9% 3 7% 4 3 3 3 4 5% 39%	2515
	11th to 20th	Night	23% 8% 2 6% 3 3 2 2 4 5% 42%	2338
	21st to end	Night	23% 7% 2 6% 4 3 3 2 5% 5% 40%	1816
March	1st to 10th	Night	21% 9% 2 5% 3 3 3 3 5% 6% 38%	4919
	11th to 20th	Night	18% 8% 3 6% 3 3 3 3 4 6% 45%	4980
	21st to end	Night	20% 9% 3 7% 4 3 3 3 3 4 41%	5467
April	1st to 10th	Night	16% 8% 2 5% 4 4 3 4 6% 6% 42%	2200
	11th to 20th	Night	16% 6% 2 5% 4 3 3 4 5% 8% 45%	2025
	21st to end	Night	16% 6% 3 5% 4 3 4 3 5% 7% 45%	2000
May	1st to 10th	Night	24% 9% 2 7% 5% 4 4 3 6% 8% 28%	4278
	11th to 20th	Night	12% 6% 2 6% 4 4 5% 4 6% 8% 42%	4053
	21st to end	Night	13% 8% 3 7% 5% 5% 5% 4 7% 10% 34%	4443
June	1st to 10th	Night	7% 4 1 4 3 3 4 5% 7% 9% 54%	1800
	11th to 20th	Night	4 3 1 4 3 4 4 3 7% 11% 56%	1800
	21st to end	Night	4 4 2 6% 5% 4 5% 6% 7% 11% 46%	1800
July	1st to 10th	Night	6% 5% 2 6% 4 5% 6% 5% 9% 14% 38%	4078
	11th to 20th	Night	4 4 2 5% 4 4 5% 5% 6% 12% 49%	4077
	21st to end	Night	7% 6% 2 7% 5% 4 5% 4 6% 9% 46%	4449
August	1st to 10th	Night	1 2 1 2 2 2 2 3 5% 10% 70%	2926
	11th to 20th	Night	2 2 1 2 2 4 4 3 8% 13% 59%	3008
	21st to end	Night	5% 3 1 5% 4 5% 5% 6% 8% 11% 47%	3679
September	1st to 10th	Night	6% 4 2 6% 4 4 4 5% 7% 9% 49%	2200
	11th to 20th	Night	10% 5% 2 7% 5% 4 5% 4 5% 8% 45%	2200
	21st to end	Night	8% 4 1 4 3 3 4 3 5% 9% 55%	2200
October	1st to 10th	Night	5% 3 2 4 3 3 3 3 5% 8% 62%	2290
	11th to 20th	Night	10% 4 1 3 2 2 3 3 4 6% 61%	2400
	21st to end	Night	12% 6% 2 4 3 2 3 2 3 4 59%	2640
November	1st to 10th	Night	11% 6% 2 4 3 4 3 2 4 6% 54%	2460
	11th to 20th	Night	12% 6% 2 5% 3 4 3 3 4 5% 52%	2520
	21st to end	Night	17% 6% 3 6% 3 3 3 3 5% 5% 45%	2615
December	1st to 10th	Night	21% 10% 3 8% 4 3 3 3 4 5% 37%	4277
	11th to 20th	Night	17% 10% 3 6% 4 3 3 3 4 5% 43%	4816
	21st to end	Night	16% 8% 2 5% 3 3 3 3 3 4 51%	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	47% 2 4 21% 19% 7%	4078
	11th to 20th	Day	39% 3 3 17% 27% 12%	4080
	21st to end	Day	53% 1 3 14% 16% 14%	4488
February	1st to 10th	Day	49% 4 5% 13% 17% 12%	1900
	11th to 20th	Day	50% 3 6% 14% 16% 10%	1959
	21st to end	Day	48% 4 7% 15% 15% 11%	1811
March	1st to 10th	Day	48% 3 7% 13% 18% 11%	4936
	11th to 20th	Day	39% 4 6% 11% 20% 19%	4980
	21st to end	Day	47% 3 7% 20% 18% 6%	5464
April	1st to 10th	Day	49% 5% 5% 16% 16% 9%	2200
	11th to 20th	Day	46% 5% 8% 15% 18% 9%	2322
	21st to end	Day	42% 6% 8% 20% 19% 6%	2400
May	1st to 10th	Day	51% 5% 9% 21% 11% 3	5657
	11th to 20th	Day	39% 5% 12% 21% 21% 2	5866
	21st to end	Day	42% 7% 11% 27% 11% 1	6447
June	1st to 10th	Day	36% 8% 15% 24% 16% 1	2600
	11th to 20th	Day	34% 8% 16% 24% 15% 3	2600
	21st to end	Day	45% 9% 16% 20% 10%	2600
July	1st to 10th	Day	42% 5% 29% 21% 3	5836
	11th to 20th	Day	40% 5% 25% 23% 7%	5831
	21st to end	Day	43% 6% 18% 24% 9%	6240
August	1st to 10th	Day	19% 6% 15% 38% 22%	4220
	11th to 20th	Day	28% 6% 30% 29% 6% 1	4083
	21st to end	Day	40% 9% 16% 20% 14% 2	4198
September	1st to 10th	Day	39% 9% 13% 18% 15% 6%	2200
	11th to 20th	Day	42% 7% 11% 20% 15% 4	2200
	21st to end	Day	34% 6% 11% 19% 18% 13%	2200
October	1st to 10th	Day	17% 3 5% 14% 22% 38%	3401
	11th to 20th	Day	24% 3 4 17% 34% 19%	3240
	21st to end	Day	29% 3 4 15% 36% 14%	3538
November	1st to 10th	Day	37% 5% 9% 17% 22% 11%	2058
	11th to 20th	Day	36% 4 9% 14% 23% 13%	2100
	21st to end	Day	44% 4 7% 17% 18% 11%	2000
December	1st to 10th	Day	48% 3 5% 17% 22% 5%	2958
	11th to 20th	Day	43% 3 7% 14% 21% 11%	3389
	21st to end	Day	42% 3 4 15% 27% 10%	4488
January	1st to 10th	Night	41% 3 5% 23% 21% 8%	5888
	11th to 20th	Night	37% 2 4 19% 27% 11%	5900
	21st to end	Night	53% 2 3 13% 17% 12%	6490
February	1st to 10th	Night	49% 3 5% 12% 16% 14%	2515
	11th to 20th	Night	46% 3 7% 15% 18% 11%	2338
	21st to end	Night	48% 4 6% 14% 15% 13%	1816
March	1st to 10th	Night	49% 3 5% 14% 20% 9%	4919
	11th to 20th	Night	41% 4 6% 14% 16% 18%	4980
	21st to end	Night	48% 3 7% 15% 19% 8%	5467
April	1st to 10th	Night	43% 5% 9% 17% 16% 10%	2200
	11th to 20th	Night	39% 4 11% 17% 16% 12%	2025
	21st to end	Night	41% 5% 9% 20% 19% 6%	2000
May	1st to 10th	Night	54% 4 9% 20% 9% 3	4308
	11th to 20th	Night	40% 4 13% 21% 19% 3	4054
	21st to end	Night	45% 6% 14% 26% 8% 1	4452
June	1st to 10th	Night	25% 7% 18% 33% 18%	1800
	11th to 20th	Night	22% 8% 19% 30% 18% 4	1800
	21st to end	Night	30% 9% 20% 27% 12% 1	1800
July	1st to 10th	Night	35% 6% 34% 22% 3	4035
	11th to 20th	Night	29% 5% 27% 31% 7%	4026
	21st to end	Night	34% 8% 20% 29% 9%	4320
August	1st to 10th	Night	13% 4 18% 44% 21% 1	2916
	11th to 20th	Night	16% 6% 35% 35% 8% 1	3035
	21st to end	Night	30% 12% 21% 26% 10% 2	3679
September	1st to 10th	Night	31% 8% 20% 20% 14% 6%	2200
	11th to 20th	Night	36% 7% 14% 21% 15% 5%	2200
	21st to end	Night	27% 5% 15% 23% 18% 12%	2200
October	1st to 10th	Night	16% 3 6% 18% 17% 39%	3745
	11th to 20th	Night	16% 3 4 23% 32% 22%	3899
	21st to end	Night	24% 2 4 17% 37% 16%	4252
November	1st to 10th	Night	33% 5% 10% 20% 22% 11%	2460
	11th to 20th	Night	35% 3 9% 18% 22% 13%	2520
	21st to end	Night	41% 4 8% 17% 19% 11%	2615
December	1st to 10th	Night	52% 2 5% 16% 19% 6%	4277
	11th to 20th	Night	45% 3 8% 9% 21% 14%	4817
	21st to end	Night	39% 3 5% 14% 30% 9%	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	29% 17% 34% 16% 3 1	300
	11th to 20th	Day	31% 15% 31% 18% 4 1	300
	21st to end	Day	30% 17% 34% 15% 4	330
February	1st to 10th	Day	27% 18% 34% 15% 5% 1	300
	11th to 20th	Day	35% 20% 28% 15% 2	300
	21st to end	Day	33% 22% 32% 10% 2	249
March	1st to 10th	Day	30% 18% 37% 11% 4	300
	11th to 20th	Day	22% 24% 36% 14% 4	300
	21st to end	Day	27% 13% 39% 16% 4	330
April	1st to 10th	Day	22% 21% 36% 17% 3	300
	11th to 20th	Day	27% 16% 27% 21% 8%	440
	21st to end	Day	19% 15% 35% 22% 7% 1	500
May	1st to 10th	Day	19% 12% 38% 23% 8% 1	590
	11th to 20th	Day	15% 6% 33% 31% 11% 2	725
	21st to end	Day	12% 8% 31% 32% 14% 3	789
June	1st to 10th	Day	7% 3 19% 36% 27% 8%	730
	11th to 20th	Day	8% 2 18% 39% 26% 6%	730
	21st to end	Day	9% 2 12% 34% 30% 13%	730
July	1st to 10th	Day	8% 5% 9% 30% 34% 14%	721
	11th to 20th	Day	4 3 4 34% 40% 15%	718
	21st to end	Day	6% 2 4 33% 42% 14%	794
August	1st to 10th	Day	3 2 3 28% 47% 16%	726
	11th to 20th	Day	5% 1 3 23% 48% 21%	640
	21st to end	Day	8% 3 7% 21% 35% 26%	522
September	1st to 10th	Day	8% 2 9% 29% 36% 15%	330
	11th to 20th	Day	10% 2 8% 33% 34% 13%	330
	21st to end	Day	9% 2 13% 36% 31% 9%	330
October	1st to 10th	Day	6% 2 20% 41% 25% 6%	330
	11th to 20th	Day	12% 6% 25% 33% 20% 5%	330
	21st to end	Day	21% 11% 26% 23% 15% 3	363
November	1st to 10th	Day	15% 9% 27% 31% 15% 3	330
	11th to 20th	Day	15% 8% 32% 34% 8% 2	330
	21st to end	Day	23% 21% 29% 20% 5% 2	330
December	1st to 10th	Day	23% 10% 36% 19% 8% 4	306
	11th to 20th	Day	25% 17% 33% 19% 5% 1	300
	21st to end	Day	25% 15% 35% 20% 5% 1	330
January	1st to 10th	Night	24% 14% 31% 24% 6%	1000
	11th to 20th	Night	24% 16% 29% 25% 6%	1000
	21st to end	Night	25% 13% 31% 26% 5%	1100
February	1st to 10th	Night	29% 14% 30% 24% 4	915
	11th to 20th	Night	30% 13% 31% 22% 4	784
	21st to end	Night	28% 16% 35% 18% 3	496
March	1st to 10th	Night	27% 12% 33% 23% 4	600
	11th to 20th	Night	23% 11% 36% 25% 6%	600
	21st to end	Night	20% 12% 40% 23% 6%	660
April	1st to 10th	Night	19% 12% 39% 26% 5%	600
	11th to 20th	Night	23% 11% 31% 28% 7%	593
	21st to end	Night	19% 9% 39% 25% 9%	600
May	1st to 10th	Night	19% 8% 36% 30% 7% 1	600
	11th to 20th	Night	17% 6% 32% 32% 10% 2	591
	21st to end	Night	11% 4 31% 34% 18% 1	650
June	1st to 10th	Night	8% 3 17% 44% 26% 3	600
	11th to 20th	Night	4 3 20% 50% 21% 2	600
	21st to end	Night	6% 2 14% 41% 31% 6%	600
July	1st to 10th	Night	5% 4 8% 44% 33% 6%	585
	11th to 20th	Night	4 1 8% 49% 33% 6%	582
	21st to end	Night	5% 2 7% 47% 34% 5%	657
August	1st to 10th	Night	3 1 4 54% 34% 5%	597
	11th to 20th	Night	5% 5% 47% 35% 7%	594
	21st to end	Night	5% 2 6% 37% 41% 9%	660
September	1st to 10th	Night	6% 2 9% 36% 39% 9%	600
	11th to 20th	Night	12% 3 9% 32% 39% 6%	600
	21st to end	Night	11% 2 13% 35% 34% 6%	600
October	1st to 10th	Night	6% 2 14% 42% 31% 4	690
	11th to 20th	Night	12% 3 25% 38% 21% 1	800
	21st to end	Night	16% 7% 28% 29% 17% 2	880
November	1st to 10th	Night	15% 5% 26% 34% 19% 2	820
	11th to 20th	Night	16% 9% 27% 33% 15%	840
	21st to end	Night	21% 10% 31% 25% 11% 2	935
December	1st to 10th	Night	24% 10% 27% 27% 11% 1	1011
	11th to 20th	Night	26% 9% 30% 28% 6% 1	1000
	21st to end	Night	25% 10% 30% 27% 8%	1100

Page generated at 2025-11-30 00:00:50. Version ac07

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