Lebanon
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lebanon clear sky chart from 2005-11-06 to 2026-09-29.

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	17% 7% 2 6% 4 4 4 3 4 6% 44%	158648
	Night	21% 8% 2 6% 4 4 4 3 4 5% 39%	150179
Transparency	Day	42% 4 12% 22% 14% 5%	153444
	Night	48% 4 12% 20% 12% 4	146381
Seeing	Day	22% 7% 21% 28% 17% 5%	17124
	Night	27% 5% 12% 31% 23% 3	26024

By Month

Percentage Cloud Cover SW (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	38% 14% 3 10% 6% 6% 5% 3 3 4 7%	4722
	11th to 20th	Day	23% 7% 2 5% 4 6% 6% 3 5% 7% 31%	4740
	21st to end	Day	27% 7% 3 7% 4 4 5% 4 5% 6% 28%	5825
February	1st to 10th	Day	29% 12% 4 8% 6% 5% 4 3 6% 7% 17%	1890
	11th to 20th	Day	30% 13% 2 8% 5% 6% 5% 3 4 5% 20%	1845
	21st to end	Day	33% 13% 3 8% 5% 4 4 3 4 5% 19%	1646
March	1st to 10th	Day	21% 13% 3 8% 5% 5% 6% 5% 7% 7% 21%	4883
	11th to 20th	Day	30% 11% 3 6% 4 4 3 3 4 4 27%	5110
	21st to end	Day	26% 11% 3 9% 6% 6% 6% 4 5% 7% 15%	5695
April	1st to 10th	Day	29% 12% 3 9% 6% 5% 4 3 5% 6% 18%	2520
	11th to 20th	Day	25% 11% 3 7% 5% 3 4 4 5% 6% 27%	2489
	21st to end	Day	26% 7% 3 6% 4 4 5% 3 6% 7% 29%	2707
May	1st to 10th	Day	14% 6% 2 5% 4 4 5% 3 5% 7% 45%	7962
	11th to 20th	Day	14% 6% 2 7% 4 5% 4 4 6% 9% 40%	8160
	21st to end	Day	14% 5% 2 6% 4 4 5% 4 5% 8% 42%	8992
June	1st to 10th	Day	23% 7% 3 7% 4 3 3 4 4 5% 37%	2940
	11th to 20th	Day	19% 6% 3 6% 4 4 4 4 5% 7% 38%	2940
	21st to end	Day	11% 4 2 5% 3 2 3 3 4 6% 57%	2940
July	1st to 10th	Day	2 2 1 2 1 2 1 2 3 4 79%	8219
	11th to 20th	Day	4 2 1 2 1 2 2 2 2 3 80%	8220
	21st to end	Day	4 2 1 2 2 2 2 2 3 4 78%	8833
August	1st to 10th	Day	3 3 1 3 2 2 2 2 3 5% 75%	7547
	11th to 20th	Day	5% 3 1 4 2 3 3 3 5% 6% 64%	7563
	21st to end	Day	7% 5% 1 3 2 3 3 3 5% 7% 61%	7940
September	1st to 10th	Day	8% 4 1 3 2 2 2 2 4 6% 66%	2520
	11th to 20th	Day	13% 5% 2 6% 4 3 3 3 4 7% 50%	2511
	21st to end	Day	15% 6% 2 5% 3 5% 3 2 5% 5% 49%	2193
October	1st to 10th	Day	15% 5% 2 4 4 3 3 3 4 5% 52%	3280
	11th to 20th	Day	20% 6% 2 6% 4 5% 5% 4 6% 7% 36%	3261
	21st to end	Day	25% 8% 2 8% 6% 5% 5% 4 6% 8% 22%	3531
November	1st to 10th	Day	33% 9% 3 8% 4 3 4 4 5% 6% 21%	1764
	11th to 20th	Day	34% 9% 3 8% 5% 5% 5% 3 5% 5% 18%	1680
	21st to end	Day	30% 9% 3 8% 5% 5% 5% 4 5% 6% 20%	1680
December	1st to 10th	Day	24% 6% 2 6% 6% 7% 7% 5% 6% 6% 26%	2700
	11th to 20th	Day	33% 12% 4 10% 7% 6% 5% 3 5% 5% 9%	3108
	21st to end	Day	37% 15% 4 10% 6% 6% 4 3 4 4 8%	4092
January	1st to 10th	Night	37% 14% 4 10% 6% 5% 4 3 4 4 10%	8172
	11th to 20th	Night	24% 9% 2 6% 5% 5% 6% 3 4 5% 32%	8220
	21st to end	Night	25% 9% 3 8% 5% 3 3 2 4 5% 32%	8373
February	1st to 10th	Night	30% 12% 3 8% 5% 5% 4 3 5% 5% 19%	2730
	11th to 20th	Night	32% 11% 3 7% 4 4 3 2 4 4 25%	2662
	21st to end	Night	33% 12% 2 6% 4 3 3 3 4 6% 23%	2159
March	1st to 10th	Night	22% 14% 4 8% 5% 5% 5% 5% 7% 6% 20%	5227
	11th to 20th	Night	27% 11% 3 6% 4 4 4 3 4 4 30%	5110
	21st to end	Night	31% 12% 3 9% 6% 5% 5% 3 4 6% 16%	5521
April	1st to 10th	Night	30% 13% 3 7% 4 4 4 3 4 5% 24%	2100
	11th to 20th	Night	24% 10% 3 7% 4 4 4 4 6% 6% 30%	2079
	21st to end	Night	26% 8% 2 6% 4 4 3 4 4 6% 32%	1910
May	1st to 10th	Night	18% 6% 2 5% 3 3 2 3 4 7% 46%	4968
	11th to 20th	Night	18% 8% 3 7% 5% 4 3 3 4 6% 39%	4700
	21st to end	Night	15% 6% 2 6% 4 4 3 3 6% 8% 43%	5181
June	1st to 10th	Night	20% 6% 3 5% 4 4 3 4 4 7% 41%	1680
	11th to 20th	Night	15% 6% 2 6% 5% 3 4 3 5% 7% 44%	1680
	21st to end	Night	11% 5% 1 4 3 2 3 2 4 4 60%	1680
July	1st to 10th	Night	3 2 1 2 1 2 2 2 4 5% 77%	4740
	11th to 20th	Night	3 2 1 2 2 2 2 1 2 3 81%	4740
	21st to end	Night	4 2 1 2 1 2 2 2 2 3 79%	5243
August	1st to 10th	Night	4 2 1 3 2 2 2 2 4 5% 74%	5275
	11th to 20th	Night	7% 3 1 4 3 3 3 3 5% 6% 62%	5292
	21st to end	Night	7% 3 1 3 3 3 3 2 4 5% 67%	6298
September	1st to 10th	Night	9% 3 1 3 2 3 3 2 3 5% 66%	2100
	11th to 20th	Night	11% 4 1 4 4 4 3 4 5% 6% 56%	2105
	21st to end	Night	13% 5% 2 5% 3 3 4 2 5% 5% 54%	2383
October	1st to 10th	Night	14% 4 2 5% 3 3 3 2 4 5% 56%	3920
	11th to 20th	Night	16% 6% 2 6% 4 4 5% 4 6% 8% 42%	3897
	21st to end	Night	25% 10% 3 8% 5% 4 4 3 5% 5% 28%	4278
November	1st to 10th	Night	31% 8% 2 7% 5% 4 5% 3 4 7% 23%	2754
	11th to 20th	Night	36% 9% 3 7% 5% 4 4 3 4 5% 21%	2940
	21st to end	Night	28% 8% 2 6% 6% 5% 5% 3 4 5% 28%	2940
December	1st to 10th	Night	21% 6% 2 6% 4 5% 5% 4 5% 7% 35%	4700
	11th to 20th	Night	36% 12% 4 10% 6% 5% 4 3 3 4 13%	5316
	21st to end	Night	35% 11% 4 12% 6% 5% 4 3 4 4 13%	7106

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	79% 5% 7% 7% 2	4723
	11th to 20th	Day	50% 3 8% 17% 14% 8%	4740
	21st to end	Day	56% 4 7% 16% 13% 5%	5825
February	1st to 10th	Day	66% 5% 11% 11% 6%	1890
	11th to 20th	Day	67% 6% 10% 10% 5% 2	1854
	21st to end	Day	69% 3 8% 11% 6% 2	1646
March	1st to 10th	Day	61% 5% 13% 17% 4	4883
	11th to 20th	Day	62% 5% 7% 18% 8% 1	5110
	21st to end	Day	68% 7% 13% 9% 3	5695
April	1st to 10th	Day	68% 5% 12% 12% 4	2520
	11th to 20th	Day	60% 5% 11% 14% 8% 2	2492
	21st to end	Day	56% 6% 14% 15% 8% 1	2707
May	1st to 10th	Day	39% 4 12% 30% 14%	7962
	11th to 20th	Day	42% 4 20% 26% 7%	8163
	21st to end	Day	41% 5% 25% 23% 5%	8994
June	1st to 10th	Day	50% 5% 15% 22% 7% 1	2940
	11th to 20th	Day	47% 5% 16% 22% 9% 1	2940
	21st to end	Day	30% 4 17% 33% 13% 4	2940
July	1st to 10th	Day	11% 2 11% 34% 24% 18%	8151
	11th to 20th	Day	13% 2 5% 16% 40% 25%	8145
	21st to end	Day	14% 2 12% 37% 30% 6%	8635
August	1st to 10th	Day	12% 3 6% 25% 36% 18%	5976
	11th to 20th	Day	20% 2 16% 41% 17% 3	5962
	21st to end	Day	22% 2 13% 34% 22% 6%	6231
September	1st to 10th	Day	22% 2 10% 31% 21% 12%	2520
	11th to 20th	Day	35% 5% 13% 24% 16% 7%	2511
	21st to end	Day	37% 4 12% 24% 17% 6%	2193
October	1st to 10th	Day	36% 3 9% 21% 24% 8%	3280
	11th to 20th	Day	46% 5% 17% 20% 11% 2	3261
	21st to end	Day	57% 5% 11% 15% 10% 1	3531
November	1st to 10th	Day	65% 4 11% 15% 5%	1764
	11th to 20th	Day	65% 6% 10% 10% 6% 2	1680
	21st to end	Day	62% 6% 10% 8% 13% 2	1680
December	1st to 10th	Day	51% 4 12% 16% 16% 1	2700
	11th to 20th	Day	72% 7% 8% 10% 2	3108
	21st to end	Day	75% 7% 8% 8% 2	4092
January	1st to 10th	Night	77% 4 8% 7% 3 1	8172
	11th to 20th	Night	53% 3 8% 16% 13% 7%	8220
	21st to end	Night	56% 2 5% 14% 16% 6%	8373
February	1st to 10th	Night	67% 5% 10% 12% 5% 1	2730
	11th to 20th	Night	63% 5% 12% 11% 7% 2	2664
	21st to end	Night	63% 5% 9% 13% 7% 2	2159
March	1st to 10th	Night	62% 4 15% 12% 6% 1	5227
	11th to 20th	Night	59% 4 11% 16% 9% 1	5110
	21st to end	Night	69% 6% 14% 9% 2	5521
April	1st to 10th	Night	65% 4 14% 12% 5%	2100
	11th to 20th	Night	57% 6% 15% 13% 6% 3	2079
	21st to end	Night	55% 6% 13% 17% 6% 3	1910
May	1st to 10th	Night	40% 4 13% 33% 10% 1	4966
	11th to 20th	Night	48% 4 14% 27% 6% 1	4700
	21st to end	Night	41% 5% 26% 25% 3	5182
June	1st to 10th	Night	44% 7% 15% 28% 6%	1680
	11th to 20th	Night	41% 5% 17% 26% 9% 1	1680
	21st to end	Night	29% 3 17% 33% 14% 4	1680
July	1st to 10th	Night	12% 2 12% 35% 21% 18%	4700
	11th to 20th	Night	12% 1 7% 17% 39% 23%	4692
	21st to end	Night	14% 1 15% 37% 27% 5%	5129
August	1st to 10th	Night	9% 2 7% 30% 34% 18%	4169
	11th to 20th	Night	21% 2 19% 41% 16% 3	4169
	21st to end	Night	20% 2 12% 40% 20% 5%	4930
September	1st to 10th	Night	23% 3 10% 30% 22% 11%	2100
	11th to 20th	Night	29% 5% 14% 29% 13% 9%	2105
	21st to end	Night	34% 4 13% 25% 17% 8%	2383
October	1st to 10th	Night	33% 3 8% 26% 27% 4	3920
	11th to 20th	Night	41% 4 22% 20% 11% 2	3897
	21st to end	Night	58% 4 9% 16% 10% 2	4278
November	1st to 10th	Night	61% 6% 11% 13% 9% 1	2754
	11th to 20th	Night	67% 5% 9% 10% 7% 2	2940
	21st to end	Night	58% 5% 10% 12% 11% 4	2940
December	1st to 10th	Night	45% 4 11% 24% 15% 1	4700
	11th to 20th	Night	72% 5% 9% 9% 4	5316
	21st to end	Night	69% 10% 10% 8% 2 1	7106

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	49% 8% 12% 16% 12% 3	220
	11th to 20th	Day	38% 5% 12% 23% 15% 7%	220
	21st to end	Day	33% 7% 17% 20% 18% 6%	468
February	1st to 10th	Day	36% 7% 16% 26% 12% 3	430
	11th to 20th	Day	36% 7% 24% 21% 9% 3	425
	21st to end	Day	36% 12% 19% 20% 11% 1	402
March	1st to 10th	Day	34% 11% 23% 23% 8% 1	540
	11th to 20th	Day	35% 8% 21% 24% 9% 4	540
	21st to end	Day	33% 12% 25% 20% 9% 1	594
April	1st to 10th	Day	34% 9% 21% 21% 11% 4	540
	11th to 20th	Day	30% 11% 24% 20% 13% 4	532
	21st to end	Day	28% 9% 23% 24% 12% 3	540
May	1st to 10th	Day	20% 10% 23% 28% 14% 5%	543
	11th to 20th	Day	26% 9% 20% 24% 15% 6%	568
	21st to end	Day	19% 8% 21% 28% 18% 7%	617
June	1st to 10th	Day	21% 9% 22% 27% 17% 5%	570
	11th to 20th	Day	17% 10% 29% 28% 13% 2	570
	21st to end	Day	9% 5% 22% 41% 17% 6%	570
July	1st to 10th	Day	5% 4 21% 42% 22% 5%	566
	11th to 20th	Day	4 5% 29% 37% 19% 6%	564
	21st to end	Day	4 3 21% 40% 23% 8%	619
August	1st to 10th	Day	4 2 20% 42% 25% 8%	567
	11th to 20th	Day	4 4 17% 42% 25% 10%	557
	21st to end	Day	7% 5% 24% 35% 22% 8%	627
September	1st to 10th	Day	9% 5% 22% 35% 22% 6%	570
	11th to 20th	Day	14% 5% 19% 30% 25% 6%	570
	21st to end	Day	17% 6% 20% 32% 20% 5%	563
October	1st to 10th	Day	20% 6% 22% 25% 19% 8%	530
	11th to 20th	Day	22% 7% 16% 27% 22% 7%	530
	21st to end	Day	28% 8% 21% 22% 16% 5%	568
November	1st to 10th	Day	34% 6% 20% 25% 11% 3	282
	11th to 20th	Day	32% 8% 21% 16% 15% 8%	220
	21st to end	Day	33% 5% 18% 20% 17% 7%	220
December	1st to 10th	Day	38% 7% 12% 19% 14% 11%	220
	11th to 20th	Day	45% 4 18% 18% 12% 3	220
	21st to end	Day	43% 6% 16% 19% 14% 3	242
January	1st to 10th	Night	42% 7% 11% 23% 14% 3	840
	11th to 20th	Night	36% 6% 9% 23% 20% 5%	840
	21st to end	Night	32% 4 10% 32% 18% 4	924
February	1st to 10th	Night	35% 5% 9% 31% 18% 2	840
	11th to 20th	Night	38% 5% 11% 29% 16% 1	824
	21st to end	Night	38% 7% 12% 25% 17%	692
March	1st to 10th	Night	35% 8% 13% 29% 15% 1	840
	11th to 20th	Night	33% 6% 13% 31% 15% 2	840
	21st to end	Night	39% 5% 14% 27% 13% 1	924
April	1st to 10th	Night	35% 7% 10% 28% 19% 1	840
	11th to 20th	Night	28% 6% 16% 31% 18% 2	831
	21st to end	Night	30% 4 12% 34% 19% 2	650
May	1st to 10th	Night	22% 5% 15% 33% 23% 2	509
	11th to 20th	Night	21% 4 12% 30% 30% 3	414
	21st to end	Night	23% 4 11% 34% 27% 2	455
June	1st to 10th	Night	20% 7% 12% 38% 21% 2	420
	11th to 20th	Night	17% 4 19% 40% 19% 1	420
	21st to end	Night	12% 3 14% 41% 29% 1	420
July	1st to 10th	Night	6% 2 13% 46% 32% 1	410
	11th to 20th	Night	6% 3 23% 42% 25% 1	408
	21st to end	Night	3 1 13% 47% 32% 3	487
August	1st to 10th	Night	4 1 7% 37% 43% 6%	627
	11th to 20th	Night	7% 1 5% 36% 46% 5%	624
	21st to end	Night	7% 3 14% 37% 33% 5%	849
September	1st to 10th	Night	9% 2 14% 36% 35% 3	840
	11th to 20th	Night	12% 3 9% 32% 37% 7%	840
	21st to end	Night	14% 3 12% 35% 31% 4	832
October	1st to 10th	Night	18% 3 12% 33% 30% 5%	800
	11th to 20th	Night	21% 3 11% 32% 27% 6%	800
	21st to end	Night	32% 4 13% 28% 18% 5%	880
November	1st to 10th	Night	34% 6% 12% 30% 17% 2	820
	11th to 20th	Night	40% 6% 12% 25% 15% 3	840
	21st to end	Night	30% 5% 10% 31% 19% 5%	840
December	1st to 10th	Night	33% 4 9% 29% 20% 5%	840
	11th to 20th	Night	41% 5% 12% 24% 16% 2	840
	21st to end	Night	44% 6% 14% 24% 11% 1	924

Page generated at 2026-09-26 01:18:45. Version ac07

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