Enif Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Enif 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	18% 7% 2 6% 4 4 4 4 5% 7% 39%	126741
	Night	18% 8% 2 6% 4 4 4 3 5% 6% 39%	123963
Transparency	Day	28% 39% 7% 15% 10% 2	130261
	Night	29% 39% 7% 14% 11% 2	128530
Seeing	Day	19% 13% 31% 25% 9% 2	16390
	Night	20% 12% 32% 26% 9% 1	25226

By Month

Percentage Cloud Cover NE (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	14% 6% 3 6% 4 5% 6% 4 6% 7% 39%	3597
	11th to 20th	Day	14% 7% 2 7% 3 3 3 3 5% 6% 46%	3570
	21st to end	Day	16% 7% 2 5% 4 4 4 3 3 5% 47%	3960
February	1st to 10th	Day	17% 8% 3 5% 4 5% 4 4 6% 7% 38%	1825
	11th to 20th	Day	13% 7% 2 7% 5% 3 5% 4 6% 7% 41%	1948
	21st to end	Day	15% 10% 3 6% 4 4 4 3 5% 6% 38%	1650
March	1st to 10th	Day	22% 10% 2 5% 4 4 4 4 5% 6% 34%	4476
	11th to 20th	Day	17% 11% 3 6% 4 4 4 3 5% 7% 39%	4832
	21st to end	Day	28% 8% 2 5% 3 3 4 3 5% 6% 32%	5689
April	1st to 10th	Day	20% 9% 2 6% 5% 4 4 3 4 6% 37%	2400
	11th to 20th	Day	17% 7% 2 5% 5% 4 5% 3 6% 7% 38%	2427
	21st to end	Day	19% 7% 3 6% 5% 4 4 3 4 7% 37%	2600
May	1st to 10th	Day	30% 9% 3 6% 4 4 3 4 5% 6% 26%	5886
	11th to 20th	Day	20% 9% 3 8% 5% 4 4 3 5% 6% 32%	5944
	21st to end	Day	20% 6% 2 6% 4 4 4 4 6% 8% 35%	6949
June	1st to 10th	Day	20% 7% 3 6% 5% 4 4 4 6% 7% 34%	2800
	11th to 20th	Day	15% 6% 2 6% 4 5% 4 3 6% 9% 40%	2800
	21st to end	Day	17% 7% 3 6% 4 5% 5% 4 6% 8% 35%	2800
July	1st to 10th	Day	15% 7% 3 7% 5% 5% 5% 5% 6% 10% 33%	6360
	11th to 20th	Day	8% 7% 2 6% 5% 5% 5% 4 7% 10% 40%	6360
	21st to end	Day	14% 5% 2 6% 4 4 4 4 6% 7% 45%	6926
August	1st to 10th	Day	14% 6% 2 7% 5% 5% 6% 4 6% 7% 39%	4268
	11th to 20th	Day	16% 8% 3 7% 4 4 4 4 5% 7% 37%	4175
	21st to end	Day	8% 3 1 4 3 5% 5% 4 8% 10% 48%	4357
September	1st to 10th	Day	12% 5% 2 4 4 3 4 4 6% 7% 48%	2374
	11th to 20th	Day	13% 5% 2 5% 4 3 3 2 4 6% 54%	2200
	21st to end	Day	16% 6% 2 5% 3 3 4 3 4 7% 46%	2200
October	1st to 10th	Day	21% 5% 2 5% 4 3 4 3 4 5% 43%	2200
	11th to 20th	Day	16% 4 2 6% 4 4 3 3 5% 7% 46%	1941
	21st to end	Day	21% 5% 3 5% 3 4 3 4 5% 6% 41%	1980
November	1st to 10th	Day	16% 6% 2 5% 3 3 3 2 4 6% 48%	1851
	11th to 20th	Day	17% 6% 2 4 2 3 3 3 5% 6% 48%	1890
	21st to end	Day	20% 8% 2 4 3 3 3 3 5% 6% 43%	1890
December	1st to 10th	Day	15% 9% 2 5% 3 3 3 4 5% 6% 46%	2670
	11th to 20th	Day	20% 5% 1 4 3 3 3 3 4 6% 47%	2986
	21st to end	Day	22% 9% 3 5% 4 4 3 3 5% 5% 37%	3960
January	1st to 10th	Night	14% 6% 2 5% 4 3 4 4 6% 7% 45%	6349
	11th to 20th	Night	13% 9% 3 9% 5% 5% 4 4 5% 6% 38%	6315
	21st to end	Night	16% 9% 2 6% 4 5% 4 3 5% 6% 40%	6996
February	1st to 10th	Night	16% 9% 3 7% 4 4 5% 4 5% 6% 38%	2570
	11th to 20th	Night	14% 9% 3 6% 5% 4 3 4 5% 6% 41%	2338
	21st to end	Night	16% 10% 2 5% 4 4 4 4 5% 6% 41%	1980
March	1st to 10th	Night	26% 9% 2 5% 3 3 4 3 4 5% 35%	5364
	11th to 20th	Night	15% 10% 3 8% 4 4 5% 3 5% 6% 37%	5126
	21st to end	Night	26% 9% 2 5% 4 3 4 3 5% 6% 32%	5240
April	1st to 10th	Night	20% 9% 2 7% 5% 4 4 3 6% 6% 36%	2000
	11th to 20th	Night	20% 7% 2 6% 4 3 4 4 4 6% 39%	1920
	21st to end	Night	21% 8% 3 7% 4 3 4 4 4 6% 38%	1800
May	1st to 10th	Night	31% 11% 3 7% 4 4 3 3 4 6% 24%	4054
	11th to 20th	Night	16% 10% 4 8% 5% 6% 5% 4 5% 8% 28%	3991
	21st to end	Night	20% 8% 3 8% 5% 4 4 4 6% 5% 32%	3926
June	1st to 10th	Night	20% 9% 3 6% 5% 4 4 3 5% 6% 35%	1600
	11th to 20th	Night	19% 7% 2 5% 3 4 5% 4 7% 9% 36%	1600
	21st to end	Night	19% 7% 2 6% 4 4 4 5% 6% 7% 36%	1600
July	1st to 10th	Night	12% 7% 3 7% 5% 6% 5% 4 6% 10% 37%	3600
	11th to 20th	Night	12% 8% 2 5% 5% 5% 5% 4 7% 8% 39%	3600
	21st to end	Night	12% 5% 2 5% 4 4 5% 4 5% 6% 47%	3926
August	1st to 10th	Night	20% 6% 2 7% 5% 5% 4 4 5% 6% 35%	2849
	11th to 20th	Night	15% 7% 3 8% 4 5% 5% 4 7% 8% 34%	2872
	21st to end	Night	10% 5% 2 4 3 4 4 4 6% 8% 50%	3537
September	1st to 10th	Night	12% 6% 2 5% 4 4 3 3 5% 7% 49%	2025
	11th to 20th	Night	14% 5% 2 4 3 3 3 2 5% 6% 52%	2200
	21st to end	Night	15% 6% 2 5% 4 4 4 3 5% 7% 45%	2200
October	1st to 10th	Night	20% 6% 2 6% 4 3 4 3 5% 6% 42%	2200
	11th to 20th	Night	16% 6% 1 5% 4 4 5% 3 5% 7% 44%	2453
	21st to end	Night	22% 7% 2 5% 4 3 3 3 5% 5% 40%	2860
November	1st to 10th	Night	14% 6% 2 5% 4 4 4 3 5% 5% 48%	2667
	11th to 20th	Night	17% 6% 2 6% 4 3 3 3 4 6% 47%	2730
	21st to end	Night	17% 7% 2 5% 3 3 4 3 5% 6% 45%	2730
December	1st to 10th	Night	17% 10% 2 5% 4 4 4 3 4 5% 41%	4541
	11th to 20th	Night	22% 7% 2 6% 3 3 3 3 4 4 42%	5208
	21st to end	Night	19% 9% 3 7% 4 3 4 3 4 5% 39%	6996

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	31% 28% 7% 20% 13% 1	3598
	11th to 20th	Day	26% 28% 9% 21% 14% 2	3600
	21st to end	Day	32% 30% 4 15% 16% 3	3960
February	1st to 10th	Day	18% 63% 5% 7% 6% 1	1825
	11th to 20th	Day	18% 61% 4 7% 8% 2	1957
	21st to end	Day	15% 62% 5% 8% 8% 2	1650
March	1st to 10th	Day	38% 30% 6% 9% 9% 9%	4479
	11th to 20th	Day	31% 32% 12% 16% 7% 2	4832
	21st to end	Day	40% 30% 4 10% 12% 5%	5689
April	1st to 10th	Day	21% 61% 2 7% 6% 2	2400
	11th to 20th	Day	16% 63% 5% 8% 6% 2	2427
	21st to end	Day	19% 62% 4 7% 8%	2600
May	1st to 10th	Day	44% 34% 9% 10% 3	5897
	11th to 20th	Day	41% 31% 10% 12% 5% 1	5948
	21st to end	Day	34% 32% 10% 15% 9%	6949
June	1st to 10th	Day	16% 62% 5% 10% 7%	2800
	11th to 20th	Day	15% 62% 5% 8% 9% 1	2800
	21st to end	Day	16% 62% 5% 10% 7% 1	2800
July	1st to 10th	Day	37% 29% 9% 14% 10%	6290
	11th to 20th	Day	27% 30% 11% 19% 11%	6285
	21st to end	Day	28% 27% 10% 23% 11% 1	6728
August	1st to 10th	Day	29% 38% 10% 16% 6%	4254
	11th to 20th	Day	30% 38% 9% 18% 5%	4214
	21st to end	Day	16% 39% 11% 21% 13% 1	4357
September	1st to 10th	Day	14% 57% 6% 14% 9%	2374
	11th to 20th	Day	17% 57% 4 11% 10% 1	2200
	21st to end	Day	17% 58% 4 13% 8% 1	2200
October	1st to 10th	Day	26% 37% 5% 17% 13% 2	3590
	11th to 20th	Day	17% 36% 5% 22% 18% 2	3131
	21st to end	Day	18% 36% 5% 24% 16% 1	3180
November	1st to 10th	Day	19% 54% 7% 12% 8% 1	1851
	11th to 20th	Day	18% 54% 3 9% 14% 2	1890
	21st to end	Day	19% 54% 6% 11% 9% 1	1890
December	1st to 10th	Day	24% 37% 9% 24% 7%	2670
	11th to 20th	Day	26% 32% 10% 12% 14% 6%	2986
	21st to end	Day	36% 28% 5% 16% 11% 4	3960
January	1st to 10th	Night	27% 27% 8% 25% 11% 2	6349
	11th to 20th	Night	35% 28% 9% 16% 10% 2	6360
	21st to end	Night	35% 30% 6% 12% 12% 5%	6996
February	1st to 10th	Night	18% 63% 5% 7% 6% 2	2570
	11th to 20th	Night	18% 61% 4 7% 9% 2	2340
	21st to end	Night	18% 62% 3 9% 6% 3	1980
March	1st to 10th	Night	39% 30% 6% 8% 11% 7%	5374
	11th to 20th	Night	34% 32% 11% 12% 10% 1	5127
	21st to end	Night	40% 30% 3 8% 14% 5%	5240
April	1st to 10th	Night	21% 62% 2 6% 7% 2	2000
	11th to 20th	Night	18% 62% 4 7% 7% 1	1920
	21st to end	Night	19% 62% 3 6% 9% 1	1800
May	1st to 10th	Night	47% 33% 9% 7% 5%	4060
	11th to 20th	Night	39% 33% 11% 11% 6%	3992
	21st to end	Night	41% 32% 9% 12% 7% 1	3927
June	1st to 10th	Night	19% 62% 3 10% 7%	1600
	11th to 20th	Night	15% 63% 6% 10% 6% 1	1600
	21st to end	Night	17% 61% 4 11% 6% 1	1600
July	1st to 10th	Night	32% 29% 9% 18% 13%	3560
	11th to 20th	Night	31% 30% 11% 14% 13%	3552
	21st to end	Night	27% 28% 10% 24% 12%	3809
August	1st to 10th	Night	36% 37% 7% 12% 8% 1	2839
	11th to 20th	Night	29% 41% 10% 13% 6%	2899
	21st to end	Night	17% 38% 11% 17% 16%	3537
September	1st to 10th	Night	14% 57% 5% 13% 9% 1	2025
	11th to 20th	Night	17% 57% 3 11% 10% 1	2200
	21st to end	Night	18% 58% 4 13% 8% 1	2200
October	1st to 10th	Night	26% 38% 9% 16% 9% 2	3590
	11th to 20th	Night	14% 36% 6% 19% 22% 2	4002
	21st to end	Night	19% 37% 6% 24% 13% 2	4610
November	1st to 10th	Night	19% 54% 4 14% 8% 2	2667
	11th to 20th	Night	18% 54% 4 10% 12% 2	2730
	21st to end	Night	18% 55% 8% 12% 7% 1	2730
December	1st to 10th	Night	29% 36% 6% 22% 8%	4541
	11th to 20th	Night	33% 32% 7% 11% 16% 1	5208
	21st to end	Night	35% 28% 6% 17% 13% 1	6996

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	26% 23% 29% 20% 4	200
	11th to 20th	Day	23% 25% 32% 18% 3 1	200
	21st to end	Day	18% 23% 37% 17% 4	220
February	1st to 10th	Day	26% 20% 37% 16% 1	393
	11th to 20th	Day	24% 25% 35% 14% 2	496
	21st to end	Day	21% 21% 36% 19% 4	414
March	1st to 10th	Day	26% 18% 35% 18% 3	500
	11th to 20th	Day	20% 23% 37% 16% 3 1	500
	21st to end	Day	24% 19% 37% 14% 5% 2	550
April	1st to 10th	Day	25% 22% 30% 17% 5% 1	500
	11th to 20th	Day	22% 18% 36% 17% 7%	492
	21st to end	Day	24% 11% 38% 19% 8% 1	500
May	1st to 10th	Day	26% 12% 36% 18% 6% 1	503
	11th to 20th	Day	17% 12% 35% 28% 6% 2	527
	21st to end	Day	20% 8% 31% 31% 9% 1	573
June	1st to 10th	Day	20% 7% 31% 29% 12% 1	530
	11th to 20th	Day	14% 9% 36% 32% 8% 2	530
	21st to end	Day	18% 6% 35% 29% 10% 2	530
July	1st to 10th	Day	15% 5% 24% 36% 16% 3	525
	11th to 20th	Day	11% 7% 24% 40% 16% 2	524
	21st to end	Day	11% 4 28% 41% 15% 2	576
August	1st to 10th	Day	11% 5% 27% 36% 18% 3	526
	11th to 20th	Day	14% 5% 24% 34% 17% 6%	519
	21st to end	Day	13% 4 26% 38% 16% 4	583
September	1st to 10th	Day	14% 6% 27% 31% 15% 7%	530
	11th to 20th	Day	16% 7% 27% 28% 14% 8%	530
	21st to end	Day	16% 9% 31% 28% 11% 5%	530
October	1st to 10th	Day	23% 11% 25% 25% 13% 4	530
	11th to 20th	Day	18% 14% 28% 27% 12% 2	447
	21st to end	Day	26% 11% 31% 23% 8%	462
November	1st to 10th	Day	16% 18% 32% 23% 9% 1	425
	11th to 20th	Day	23% 22% 30% 21% 4	430
	21st to end	Day	26% 21% 28% 20% 5%	430
December	1st to 10th	Day	21% 21% 33% 19% 6%	245
	11th to 20th	Day	23% 21% 39% 16% 2	200
	21st to end	Day	22% 21% 31% 20% 5% 1	220
January	1st to 10th	Night	21% 20% 40% 17% 3	800
	11th to 20th	Night	25% 17% 38% 18% 3	800
	21st to end	Night	19% 22% 38% 18% 4	880
February	1st to 10th	Night	23% 17% 38% 21% 1	800
	11th to 20th	Night	23% 20% 40% 15% 3	783
	21st to end	Night	21% 16% 37% 23% 3	660
March	1st to 10th	Night	25% 17% 37% 18% 3	800
	11th to 20th	Night	21% 16% 37% 20% 6%	800
	21st to end	Night	24% 15% 35% 21% 5%	880
April	1st to 10th	Night	25% 15% 33% 23% 4	800
	11th to 20th	Night	23% 13% 34% 24% 6%	736
	21st to end	Night	23% 11% 33% 29% 4 1	600
May	1st to 10th	Night	27% 7% 32% 25% 8% 1	600
	11th to 20th	Night	21% 8% 34% 29% 7% 1	576
	21st to end	Night	21% 6% 26% 36% 10%	433
June	1st to 10th	Night	22% 5% 25% 35% 12% 2	400
	11th to 20th	Night	20% 6% 25% 38% 12% 1	400
	21st to end	Night	20% 3 24% 40% 13%	400
July	1st to 10th	Night	17% 3 20% 44% 15% 1	390
	11th to 20th	Night	12% 4 17% 47% 19% 1	388
	21st to end	Night	13% 3 18% 47% 16% 2	438
August	1st to 10th	Night	15% 3 18% 41% 23% 1	557
	11th to 20th	Night	14% 5% 20% 41% 18% 3	592
	21st to end	Night	14% 4 24% 35% 22% 2	844
September	1st to 10th	Night	13% 4 27% 34% 20% 1	800
	11th to 20th	Night	16% 5% 26% 30% 20% 4	800
	21st to end	Night	18% 4 27% 31% 17% 3	800
October	1st to 10th	Night	21% 8% 26% 29% 15% 1	800
	11th to 20th	Night	18% 11% 30% 30% 11% 1	800
	21st to end	Night	25% 11% 32% 25% 7%	880
November	1st to 10th	Night	16% 12% 35% 28% 7% 1	820
	11th to 20th	Night	20% 17% 35% 21% 6% 1	840
	21st to end	Night	21% 19% 33% 22% 4 1	840
December	1st to 10th	Night	24% 14% 40% 18% 4	809
	11th to 20th	Night	22% 19% 34% 21% 3	800
	21st to end	Night	25% 16% 36% 21% 2	880

Page generated at 2025-11-30 01:00:54. Version ac07

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