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 2024-01-13.

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% 3 5% 5% 3 5% 5% 6% 7% 42%	74949
	Night	13% 6% 2 4 4 2 4 4 5% 7% 48%	74799
Transparency	Day	41% 6% 11% 18% 16% 7%	74674
	Night	36% 6% 12% 20% 18% 9%	74594
Seeing	Day	14% 8% 21% 27% 22% 8%	13752
	Night	17% 8% 25% 32% 17% 2	23731

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% 6% 2 4 4 2 3 4 4 6% 46%	1707
	11th to 20th	Day	20% 6% 3 5% 5% 2 3 3 4 6% 44%	1638
	21st to end	Day	19% 7% 2 5% 3 2 3 4 4 6% 44%	1782
February	1st to 10th	Day	24% 7% 4 5% 4 2 3 3 4 6% 38%	1710
	11th to 20th	Day	22% 8% 3 6% 5% 2 3 3 3 6% 39%	1749
	21st to end	Day	21% 7% 4 5% 5% 3 3 2 3 6% 41%	1624
March	1st to 10th	Day	21% 8% 3 6% 6% 3 4 4 4 6% 36%	1980
	11th to 20th	Day	19% 7% 3 6% 4 3 3 4 4 7% 39%	1980
	21st to end	Day	16% 7% 3 5% 5% 2 5% 4 4 6% 43%	2178
April	1st to 10th	Day	17% 7% 3 6% 6% 3 4 5% 4 6% 37%	1980
	11th to 20th	Day	18% 6% 3 5% 5% 4 5% 4 5% 6% 39%	2086
	21st to end	Day	13% 6% 2 5% 5% 3 5% 4 6% 7% 44%	2160
May	1st to 10th	Day	12% 7% 2 6% 6% 4 7% 6% 6% 7% 38%	2237
	11th to 20th	Day	11% 6% 2 6% 5% 4 5% 5% 6% 8% 41%	2302
	21st to end	Day	10% 6% 4 7% 7% 4 7% 7% 7% 10% 32%	2531
June	1st to 10th	Day	7% 4 3 5% 6% 4 6% 7% 7% 9% 42%	2340
	11th to 20th	Day	6% 3 1 4 5% 4 7% 6% 8% 12% 43%	2340
	21st to end	Day	8% 4 3 7% 8% 6% 8% 8% 9% 8% 31%	2340
July	1st to 10th	Day	11% 5% 3 6% 7% 4 7% 6% 8% 10% 33%	2340
	11th to 20th	Day	6% 4 2 5% 7% 5% 8% 6% 8% 11% 39%	2340
	21st to end	Day	5% 4 3 6% 7% 4 7% 8% 9% 11% 36%	2546
August	1st to 10th	Day	3 2 2 5% 6% 4 6% 6% 8% 12% 46%	2328
	11th to 20th	Day	5% 4 2 5% 6% 5% 7% 7% 7% 10% 42%	2234
	21st to end	Day	7% 4 2 7% 7% 5% 6% 8% 8% 10% 38%	2322
September	1st to 10th	Day	6% 5% 3 5% 7% 3 6% 6% 7% 9% 42%	1980
	11th to 20th	Day	13% 6% 3 7% 7% 5% 6% 5% 5% 7% 37%	1980
	21st to end	Day	8% 4 2 6% 5% 3 6% 5% 6% 7% 47%	1980
October	1st to 10th	Day	8% 3 2 3 5% 3 4 4 5% 6% 57%	1881
	11th to 20th	Day	11% 5% 2 6% 4 4 4 4 4 6% 51%	1800
	21st to end	Day	14% 5% 2 4 4 2 3 3 4 4 55%	1980
November	1st to 10th	Day	11% 5% 2 5% 5% 2 4 5% 6% 7% 47%	1858
	11th to 20th	Day	11% 6% 3 4 5% 2 3 5% 5% 6% 49%	1900
	21st to end	Day	17% 6% 3 5% 5% 3 5% 3 4 5% 43%	1810
December	1st to 10th	Day	15% 8% 2 5% 6% 3 4 4 4 6% 41%	1710
	11th to 20th	Day	15% 7% 4 6% 6% 3 4 4 4 6% 42%	2161
	21st to end	Day	18% 7% 2 5% 4 2 4 3 4 5% 46%	3135
January	1st to 10th	Night	19% 7% 2 4 3 2 2 3 4 6% 47%	2458
	11th to 20th	Night	20% 6% 3 4 4 2 2 3 4 5% 48%	2367
	21st to end	Night	19% 7% 2 4 5% 2 3 4 4 6% 45%	2574
February	1st to 10th	Night	20% 9% 3 6% 5% 2 3 4 3 5% 40%	2264
	11th to 20th	Night	23% 7% 2 5% 3 2 3 3 3 5% 43%	2098
	21st to end	Night	24% 6% 2 5% 5% 2 3 3 5% 6% 39%	1629
March	1st to 10th	Night	19% 7% 3 5% 4 2 4 4 5% 6% 40%	1980
	11th to 20th	Night	17% 8% 3 5% 4 3 4 4 6% 7% 41%	1980
	21st to end	Night	15% 7% 2 4 4 2 3 3 4 6% 49%	2178
April	1st to 10th	Night	14% 7% 3 4 5% 3 4 5% 6% 7% 42%	1980
	11th to 20th	Night	17% 6% 2 4 5% 2 3 4 4 8% 45%	1821
	21st to end	Night	14% 5% 3 4 4 2 4 4 5% 7% 47%	1800
May	1st to 10th	Night	14% 6% 1 5% 7% 3 5% 5% 6% 8% 42%	1718
	11th to 20th	Night	14% 4 2 5% 4 2 4 4 5% 8% 47%	1593
	21st to end	Night	8% 4 3 4 4 3 5% 5% 7% 10% 47%	1745
June	1st to 10th	Night	6% 3 1 4 4 2 4 5% 6% 10% 54%	1620
	11th to 20th	Night	4 2 1 3 3 3 4 5% 7% 12% 57%	1620
	21st to end	Night	5% 4 2 6% 5% 3 5% 6% 7% 11% 45%	1620
July	1st to 10th	Night	7% 3 2 4 4 3 5% 6% 8% 11% 46%	1620
	11th to 20th	Night	3 2 2 3 4 2 5% 5% 6% 12% 57%	1620
	21st to end	Night	3 2 1 3 4 3 5% 6% 7% 13% 52%	1772
August	1st to 10th	Night	2 2 1 2 3 2 3 3 6% 13% 63%	1611
	11th to 20th	Night	4 3 1 3 4 3 5% 6% 8% 13% 52%	1664
	21st to end	Night	5% 2 1 5% 5% 4 5% 7% 7% 11% 47%	2028
September	1st to 10th	Night	5% 4 2 5% 5% 3 4 5% 7% 9% 50%	1980
	11th to 20th	Night	11% 5% 2 6% 6% 3 4 6% 5% 8% 44%	1980
	21st to end	Night	9% 4 1 4 4 2 3 4 5% 9% 55%	1980
October	1st to 10th	Night	5% 3 2 3 4 3 3 3 4 8% 61%	2060
	11th to 20th	Night	12% 4 1 3 3 2 3 4 5% 6% 58%	2160
	21st to end	Night	13% 6% 2 4 3 2 3 2 3 4 58%	2376
November	1st to 10th	Night	11% 5% 2 4 4 3 4 3 5% 6% 54%	2220
	11th to 20th	Night	13% 6% 2 4 4 3 4 4 5% 6% 50%	2280
	21st to end	Night	18% 6% 3 5% 4 2 4 4 5% 5% 44%	2365
December	1st to 10th	Night	19% 8% 3 4 4 2 4 4 4 5% 43%	2470
	11th to 20th	Night	17% 9% 3 6% 4 2 4 3 4 6% 42%	3036
	21st to end	Night	17% 7% 2 4 4 2 3 4 4 5% 47%	4532

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	41% 3 7% 16% 23% 10%	1708
	11th to 20th	Day	44% 3 5% 16% 21% 11%	1638
	21st to end	Day	43% 3 5% 15% 21% 13%	1782
February	1st to 10th	Day	50% 4 5% 14% 16% 12%	1710
	11th to 20th	Day	50% 3 7% 13% 17% 10%	1759
	21st to end	Day	48% 4 7% 14% 14% 11%	1624
March	1st to 10th	Day	51% 4 8% 13% 18% 7%	1980
	11th to 20th	Day	47% 4 8% 13% 19% 10%	1980
	21st to end	Day	44% 4 8% 14% 22% 7%	2178
April	1st to 10th	Day	49% 5% 5% 18% 15% 8%	1980
	11th to 20th	Day	46% 4 8% 15% 17% 9%	2086
	21st to end	Day	40% 5% 8% 20% 20% 6%	2160
May	1st to 10th	Day	44% 7% 10% 15% 16% 7%	2237
	11th to 20th	Day	40% 7% 10% 22% 18% 3	2306
	21st to end	Day	45% 9% 13% 21% 11% 1	2531
June	1st to 10th	Day	36% 8% 15% 24% 16% 2	2340
	11th to 20th	Day	33% 9% 16% 25% 14% 3	2340
	21st to end	Day	46% 10% 15% 19% 9%	2340
July	1st to 10th	Day	43% 10% 18% 22% 6% 1	2276
	11th to 20th	Day	37% 11% 20% 21% 10% 1	2271
	21st to end	Day	36% 11% 22% 24% 7% 1	2405
August	1st to 10th	Day	28% 11% 22% 27% 11% 1	2314
	11th to 20th	Day	35% 10% 20% 24% 9% 2	2234
	21st to end	Day	40% 10% 17% 22% 8% 3	2322
September	1st to 10th	Day	38% 9% 14% 19% 14% 6%	1980
	11th to 20th	Day	44% 8% 12% 17% 14% 4	1980
	21st to end	Day	35% 7% 12% 18% 18% 11%	1980
October	1st to 10th	Day	27% 6% 9% 24% 21% 13%	1881
	11th to 20th	Day	35% 5% 6% 17% 21% 16%	1800
	21st to end	Day	35% 4 5% 14% 25% 17%	1980
November	1st to 10th	Day	36% 5% 9% 18% 21% 10%	1858
	11th to 20th	Day	38% 4 9% 14% 23% 13%	1900
	21st to end	Day	44% 5% 6% 16% 17% 11%	1810
December	1st to 10th	Day	45% 5% 8% 17% 18% 7%	1710
	11th to 20th	Day	43% 4 7% 14% 22% 10%	2159
	21st to end	Day	42% 4 5% 14% 24% 11%	3135
January	1st to 10th	Night	40% 3 6% 18% 21% 12%	2458
	11th to 20th	Night	41% 3 6% 17% 21% 12%	2367
	21st to end	Night	43% 3 5% 16% 19% 15%	2574
February	1st to 10th	Night	48% 3 5% 13% 17% 14%	2264
	11th to 20th	Night	44% 4 7% 15% 18% 12%	2098
	21st to end	Night	48% 4 6% 13% 14% 14%	1629
March	1st to 10th	Night	45% 5% 7% 16% 18% 9%	1980
	11th to 20th	Night	43% 6% 11% 12% 19% 9%	1980
	21st to end	Night	39% 3 12% 15% 21% 9%	2178
April	1st to 10th	Night	42% 5% 10% 18% 16% 9%	1980
	11th to 20th	Night	39% 4 12% 17% 16% 12%	1821
	21st to end	Night	39% 5% 8% 21% 21% 7%	1800
May	1st to 10th	Night	42% 5% 10% 19% 16% 8%	1718
	11th to 20th	Night	36% 6% 12% 24% 18% 4	1594
	21st to end	Night	32% 7% 17% 29% 12% 2	1746
June	1st to 10th	Night	24% 8% 18% 32% 18%	1620
	11th to 20th	Night	21% 8% 19% 30% 19% 3	1620
	21st to end	Night	31% 10% 19% 27% 12% 1	1620
July	1st to 10th	Night	29% 11% 26% 27% 6%	1575
	11th to 20th	Night	20% 9% 31% 30% 10%	1566
	21st to end	Night	19% 13% 30% 31% 7%	1673
August	1st to 10th	Night	13% 7% 30% 37% 12% 1	1601
	11th to 20th	Night	21% 10% 29% 30% 9% 1	1664
	21st to end	Night	28% 12% 23% 26% 8% 3	2028
September	1st to 10th	Night	30% 8% 22% 21% 13% 6%	1980
	11th to 20th	Night	37% 8% 15% 20% 14% 6%	1980
	21st to end	Night	28% 6% 15% 22% 19% 11%	1980
October	1st to 10th	Night	24% 4 11% 29% 18% 14%	2060
	11th to 20th	Night	27% 5% 7% 20% 25% 16%	2160
	21st to end	Night	31% 3 6% 16% 23% 20%	2376
November	1st to 10th	Night	32% 5% 10% 21% 21% 11%	2220
	11th to 20th	Night	36% 4 9% 18% 21% 12%	2280
	21st to end	Night	42% 4 7% 17% 19% 11%	2365
December	1st to 10th	Night	44% 4 8% 19% 15% 9%	2470
	11th to 20th	Night	46% 4 6% 10% 20% 14%	3037
	21st to end	Night	40% 4 6% 13% 28% 8%	4532

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	27% 16% 36% 16% 3 1	270
	11th to 20th	Day	29% 11% 33% 20% 5% 2	246
	21st to end	Day	26% 18% 37% 16% 3	264
February	1st to 10th	Day	29% 20% 32% 15% 4 1	240
	11th to 20th	Day	33% 22% 28% 15% 3	240
	21st to end	Day	34% 22% 34% 9% 1 1	198
March	1st to 10th	Day	29% 18% 38% 12% 4	240
	11th to 20th	Day	20% 25% 33% 16% 5%	240
	21st to end	Day	27% 11% 39% 17% 5%	264
April	1st to 10th	Day	20% 22% 38% 18% 3	240
	11th to 20th	Day	27% 16% 26% 21% 9% 1	364
	21st to end	Day	18% 14% 36% 23% 8% 1	420
May	1st to 10th	Day	18% 11% 36% 25% 9% 1	500
	11th to 20th	Day	14% 6% 32% 33% 12% 3	625
	21st to end	Day	12% 7% 28% 34% 15% 4	679
June	1st to 10th	Day	7% 2 16% 37% 28% 8%	630
	11th to 20th	Day	7% 1 17% 40% 27% 7%	630
	21st to end	Day	10% 2 11% 34% 30% 13%	630
July	1st to 10th	Day	8% 4 9% 31% 34% 14%	621
	11th to 20th	Day	3 2 4 32% 42% 16%	618
	21st to end	Day	4 2 3 32% 45% 15%	684
August	1st to 10th	Day	3 2 3 28% 48% 16%	626
	11th to 20th	Day	5% 1 2 23% 48% 20%	548
	21st to end	Day	8% 2 6% 19% 36% 28%	441
September	1st to 10th	Day	7% 2 3 27% 42% 18%	270
	11th to 20th	Day	11% 1 8% 32% 35% 12%	270
	21st to end	Day	11% 2 9% 37% 32% 9%	270
October	1st to 10th	Day	7% 3 17% 40% 27% 6%	270
	11th to 20th	Day	13% 6% 27% 29% 19% 6%	270
	21st to end	Day	23% 11% 26% 22% 15% 3	297
November	1st to 10th	Day	14% 7% 25% 35% 16% 3	270
	11th to 20th	Day	18% 8% 33% 31% 8% 2	270
	21st to end	Day	24% 21% 29% 20% 4 3	270
December	1st to 10th	Day	21% 9% 36% 21% 9% 4	270
	11th to 20th	Day	26% 18% 33% 19% 4	270
	21st to end	Day	24% 16% 35% 20% 5% 1	297
January	1st to 10th	Night	24% 14% 31% 25% 7%	950
	11th to 20th	Night	24% 15% 28% 26% 6%	911
	21st to end	Night	23% 13% 32% 26% 5%	990
February	1st to 10th	Night	28% 14% 30% 24% 4	824
	11th to 20th	Night	29% 12% 31% 23% 4	704
	21st to end	Night	28% 16% 35% 19% 3	445
March	1st to 10th	Night	26% 11% 33% 24% 5%	540
	11th to 20th	Night	22% 10% 35% 26% 6%	540
	21st to end	Night	19% 11% 39% 24% 6%	594
April	1st to 10th	Night	17% 10% 41% 26% 5%	540
	11th to 20th	Night	22% 10% 32% 28% 8%	533
	21st to end	Night	17% 9% 40% 25% 9%	540
May	1st to 10th	Night	17% 8% 36% 31% 7% 1	540
	11th to 20th	Night	17% 5% 31% 34% 11% 2	531
	21st to end	Night	10% 4 29% 36% 20% 2	584
June	1st to 10th	Night	8% 2 15% 46% 26% 3	540
	11th to 20th	Night	4 3 20% 50% 21% 2	540
	21st to end	Night	6% 2 14% 41% 31% 6%	540
July	1st to 10th	Night	5% 3 8% 45% 32% 6%	525
	11th to 20th	Night	3 8% 49% 33% 6%	522
	21st to end	Night	4 2 7% 48% 35% 5%	591
August	1st to 10th	Night	2 4 55% 33% 4	537
	11th to 20th	Night	5% 5% 48% 33% 8%	534
	21st to end	Night	6% 2 5% 37% 41% 9%	594
September	1st to 10th	Night	6% 2 6% 34% 42% 9%	540
	11th to 20th	Night	13% 3 8% 32% 39% 6%	540
	21st to end	Night	12% 2 13% 34% 34% 6%	540
October	1st to 10th	Night	6% 3 14% 41% 32% 4	620
	11th to 20th	Night	13% 4 24% 37% 20% 2	720
	21st to end	Night	17% 6% 28% 29% 17% 3	792
November	1st to 10th	Night	13% 4 27% 36% 18% 2	740
	11th to 20th	Night	17% 10% 26% 33% 15%	760
	21st to end	Night	21% 10% 30% 26% 12% 2	845
December	1st to 10th	Night	23% 9% 27% 28% 11% 1	950
	11th to 20th	Night	26% 9% 30% 27% 6% 1	950
	21st to end	Night	25% 10% 30% 27% 9%	1045

Page generated at 2024-01-10 00:25:01. Version ac07

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