Elevation Estates
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Elevation Estates 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	9% 5% 2 5% 3 3 4 3 5% 7% 55%	101323
	Night	9% 5% 2 4 3 3 3 3 4 7% 58%	98407
Transparency	Day	28% 5% 9% 24% 24% 9%	105105
	Night	26% 4 8% 23% 26% 12%	102752
Seeing	Day	10% 6% 22% 29% 24% 9%	15196
	Night	11% 6% 29% 37% 16% 1	25111

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	11% 5% 2 4 3 3 3 2 4 5% 57%	2847
	11th to 20th	Day	9% 5% 2 4 3 2 2 3 4 5% 63%	2850
	21st to end	Day	18% 10% 2 4 2 2 2 2 3 4 49%	3144
February	1st to 10th	Day	13% 6% 2 6% 3 4 3 2 4 6% 51%	1900
	11th to 20th	Day	14% 7% 2 5% 3 3 3 3 4 6% 50%	1849
	21st to end	Day	18% 8% 2 3 2 2 2 2 2 4 55%	1570
March	1st to 10th	Day	13% 6% 2 4 3 3 3 3 5% 6% 52%	3393
	11th to 20th	Day	14% 7% 2 5% 4 4 4 4 4 6% 45%	3480
	21st to end	Day	9% 7% 2 6% 4 4 4 4 6% 8% 46%	3814
April	1st to 10th	Day	9% 5% 2 5% 5% 4 4 4 5% 6% 51%	2090
	11th to 20th	Day	12% 5% 2 6% 3 3 3 3 5% 5% 52%	2134
	21st to end	Day	10% 5% 2 6% 3 3 4 4 5% 6% 53%	2470
May	1st to 10th	Day	15% 7% 2 6% 4 4 4 3 5% 6% 43%	4082
	11th to 20th	Day	14% 6% 2 6% 4 3 4 3 5% 5% 50%	4082
	21st to end	Day	12% 6% 2 6% 4 5% 5% 4 7% 8% 40%	4477
June	1st to 10th	Day	5% 3 2 5% 4 3 4 5% 6% 8% 55%	2470
	11th to 20th	Day	4 3 1 4 4 4 4 4 7% 9% 56%	2470
	21st to end	Day	4 4 2 4 4 4 5% 3 5% 8% 58%	2470
July	1st to 10th	Day	4 4 1 5% 4 4 5% 4 6% 7% 55%	4120
	11th to 20th	Day	3 2 1 3 3 3 3 3 6% 9% 64%	4120
	21st to end	Day	5% 4 2 5% 4 4 5% 5% 8% 10% 51%	4465
August	1st to 10th	Day	1 1 1 2 3 4 3 3 4 8% 70%	4104
	11th to 20th	Day	4 2 1 3 3 3 3 3 6% 9% 64%	3959
	21st to end	Day	3 2 1 4 3 4 4 4 6% 8% 62%	4033
September	1st to 10th	Day	9% 4 1 5% 4 3 4 4 4 7% 54%	2090
	11th to 20th	Day	10% 3 2 6% 4 6% 4 4 6% 6% 48%	2090
	21st to end	Day	7% 4 1 4 3 3 4 3 6% 7% 59%	2090
October	1st to 10th	Day	6% 2 1 4 3 3 3 3 4 6% 65%	2090
	11th to 20th	Day	10% 4 1 3 2 2 2 3 4 5% 64%	1910
	21st to end	Day	12% 3 1 5% 2 2 2 1 3 3 64%	2090
November	1st to 10th	Day	12% 5% 2 5% 3 3 3 2 3 6% 57%	1955
	11th to 20th	Day	7% 3 1 4 3 3 3 3 4 7% 64%	1800
	21st to end	Day	14% 6% 2 4 3 2 3 3 4 5% 55%	1800
December	1st to 10th	Day	12% 7% 2 4 3 3 3 3 6% 6% 53%	1719
	11th to 20th	Day	13% 7% 2 6% 4 3 4 3 4 6% 49%	2161
	21st to end	Day	16% 6% 2 5% 4 3 3 3 3 4 52%	3135
January	1st to 10th	Night	14% 3 1 3 2 3 2 2 3 6% 61%	4108
	11th to 20th	Night	11% 4 1 3 2 2 2 2 3 4 65%	4120
	21st to end	Night	16% 8% 3 5% 3 2 2 3 3 5% 50%	4532
February	1st to 10th	Night	13% 6% 2 4 3 3 3 2 4 5% 54%	2285
	11th to 20th	Night	13% 6% 2 5% 3 3 2 2 5% 6% 53%	2218
	21st to end	Night	15% 5% 2 4 3 3 2 2 4 5% 55%	1884
March	1st to 10th	Night	12% 7% 3 6% 3 4 4 4 4 5% 48%	3462
	11th to 20th	Night	13% 5% 2 5% 4 3 3 3 5% 7% 50%	3480
	21st to end	Night	10% 6% 2 6% 3 4 4 3 5% 6% 50%	3817
April	1st to 10th	Night	8% 4 2 5% 3 3 3 3 5% 7% 56%	2090
	11th to 20th	Night	12% 4 2 5% 3 3 4 3 5% 6% 54%	1990
	21st to end	Night	10% 4 1 4 3 3 4 3 3 6% 58%	1710
May	1st to 10th	Night	16% 9% 2 5% 3 3 4 3 5% 6% 42%	2823
	11th to 20th	Night	9% 7% 2 6% 4 3 4 3 4 6% 51%	2823
	21st to end	Night	10% 5% 2 5% 3 3 4 3 5% 8% 52%	3090
June	1st to 10th	Night	3 2 1 4 3 3 4 4 6% 11% 60%	1710
	11th to 20th	Night	2 2 1 3 2 3 3 4 6% 9% 65%	1710
	21st to end	Night	3 2 1 4 3 3 3 4 6% 7% 63%	1710
July	1st to 10th	Night	4 2 1 3 3 3 4 3 5% 9% 62%	2850
	11th to 20th	Night	2 1 1 2 2 2 3 3 5% 10% 70%	2850
	21st to end	Night	3 3 1 4 3 3 4 4 6% 9% 60%	3098
August	1st to 10th	Night	1 1 1 2 1 2 2 4 9% 78%	2836
	11th to 20th	Night	3 2 1 2 2 2 3 2 6% 11% 67%	2862
	21st to end	Night	2 2 1 3 3 3 4 3 5% 10% 65%	3628
September	1st to 10th	Night	7% 5% 2 4 2 3 3 3 4 8% 58%	2090
	11th to 20th	Night	9% 5% 2 5% 4 4 4 3 6% 7% 53%	2090
	21st to end	Night	7% 3 1 3 3 3 3 3 4 8% 63%	2090
October	1st to 10th	Night	5% 3 1 3 3 3 3 2 4 8% 66%	2090
	11th to 20th	Night	9% 3 2 3 2 2 3 2 3 5% 66%	2249
	21st to end	Night	13% 4 2 3 2 2 2 2 3 4 63%	2508
November	1st to 10th	Night	9% 5% 1 4 3 2 4 2 3 5% 61%	2340
	11th to 20th	Night	5% 4 2 4 3 2 3 3 5% 6% 63%	2600
	21st to end	Night	14% 6% 2 4 3 2 3 3 3 6% 54%	2600
December	1st to 10th	Night	11% 5% 2 4 3 3 2 3 4 6% 58%	2496
	11th to 20th	Night	11% 7% 2 5% 4 3 3 3 4 6% 53%	3036
	21st to end	Night	15% 6% 1 4 3 3 2 2 4 5% 56%	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	29% 4 5% 19% 35% 8%	2848
	11th to 20th	Day	26% 2 7% 20% 34% 10%	2850
	21st to end	Day	40% 3 5% 18% 25% 10%	3144
February	1st to 10th	Day	36% 4 4 20% 23% 13%	1900
	11th to 20th	Day	37% 3 7% 20% 22% 11%	1859
	21st to end	Day	37% 2 4 14% 26% 18%	1570
March	1st to 10th	Day	32% 5% 5% 15% 29% 14%	3393
	11th to 20th	Day	39% 6% 12% 20% 17% 5%	3480
	21st to end	Day	33% 7% 12% 21% 18% 8%	3814
April	1st to 10th	Day	33% 5% 9% 21% 19% 13%	2090
	11th to 20th	Day	34% 5% 8% 22% 20% 11%	2134
	21st to end	Day	32% 5% 8% 21% 26% 7%	2470
May	1st to 10th	Day	40% 7% 9% 19% 17% 8%	4120
	11th to 20th	Day	36% 4 9% 22% 26% 2	4086
	21st to end	Day	38% 9% 12% 23% 12% 6%	4489
June	1st to 10th	Day	26% 7% 14% 31% 19% 4	2470
	11th to 20th	Day	23% 6% 13% 30% 20% 7%	2470
	21st to end	Day	24% 6% 11% 26% 26% 7%	2470
July	1st to 10th	Day	26% 6% 14% 40% 13% 1	4056
	11th to 20th	Day	16% 5% 12% 39% 24% 4	4051
	21st to end	Day	25% 7% 13% 35% 19% 1	4325
August	1st to 10th	Day	14% 3 10% 29% 38% 5%	4090
	11th to 20th	Day	18% 4 14% 38% 25% 2	3998
	21st to end	Day	19% 6% 16% 35% 20% 3	4032
September	1st to 10th	Day	29% 7% 9% 20% 25% 11%	2090
	11th to 20th	Day	34% 7% 10% 19% 22% 9%	2090
	21st to end	Day	24% 4 9% 21% 28% 14%	2090
October	1st to 10th	Day	13% 2 6% 14% 35% 29%	3480
	11th to 20th	Day	16% 2 6% 20% 36% 20%	3150
	21st to end	Day	21% 2 4 27% 32% 13%	3428
November	1st to 10th	Day	30% 5% 6% 21% 25% 13%	1955
	11th to 20th	Day	22% 4 9% 21% 29% 16%	1800
	21st to end	Day	33% 3 5% 21% 25% 13%	1800
December	1st to 10th	Day	32% 4 7% 22% 26% 8%	1719
	11th to 20th	Day	38% 4 5% 15% 25% 12%	2159
	21st to end	Day	36% 3 4 22% 23% 12%	3135
January	1st to 10th	Night	28% 2 5% 18% 34% 12%	4108
	11th to 20th	Night	25% 2 5% 20% 30% 17%	4120
	21st to end	Night	38% 4 5% 16% 26% 12%	4532
February	1st to 10th	Night	35% 4 6% 17% 23% 16%	2285
	11th to 20th	Night	33% 3 7% 15% 29% 12%	2218
	21st to end	Night	33% 4 5% 16% 23% 19%	1884
March	1st to 10th	Night	37% 6% 5% 14% 23% 15%	3462
	11th to 20th	Night	33% 6% 11% 24% 17% 8%	3480
	21st to end	Night	34% 5% 8% 20% 27% 6%	3817
April	1st to 10th	Night	28% 4 9% 23% 19% 17%	2090
	11th to 20th	Night	31% 5% 10% 18% 20% 16%	1990
	21st to end	Night	28% 4 10% 21% 30% 7%	1710
May	1st to 10th	Night	42% 7% 8% 21% 14% 9%	2850
	11th to 20th	Night	34% 6% 12% 22% 24% 3	2824
	21st to end	Night	29% 8% 13% 29% 15% 6%	3099
June	1st to 10th	Night	18% 8% 13% 34% 21% 6%	1710
	11th to 20th	Night	15% 5% 13% 35% 24% 8%	1710
	21st to end	Night	19% 7% 11% 27% 28% 8%	1710
July	1st to 10th	Night	19% 5% 13% 45% 15% 3	2805
	11th to 20th	Night	11% 4 9% 43% 28% 5%	2796
	21st to end	Night	20% 5% 14% 37% 22% 1	2999
August	1st to 10th	Night	7% 2 9% 35% 41% 7%	2826
	11th to 20th	Night	14% 3 14% 37% 27% 5%	2889
	21st to end	Night	16% 6% 20% 34% 21% 3	3628
September	1st to 10th	Night	26% 5% 8% 22% 26% 12%	2090
	11th to 20th	Night	31% 5% 12% 19% 22% 11%	2090
	21st to end	Night	21% 4 7% 23% 27% 17%	2090
October	1st to 10th	Night	12% 2 5% 15% 29% 37%	3480
	11th to 20th	Night	15% 2 6% 19% 33% 25%	3735
	21st to end	Night	22% 2 3 22% 36% 15%	4120
November	1st to 10th	Night	27% 4 6% 21% 26% 17%	2340
	11th to 20th	Night	22% 5% 6% 23% 27% 18%	2600
	21st to end	Night	33% 3 6% 17% 28% 13%	2600
December	1st to 10th	Night	28% 4 6% 24% 25% 13%	2496
	11th to 20th	Night	33% 3 5% 16% 28% 15%	3037
	21st to end	Night	33% 3 5% 17% 27% 15%	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	17% 11% 36% 28% 9%	270
	11th to 20th	Day	16% 14% 31% 28% 9% 2	270
	21st to end	Day	18% 10% 37% 23% 11% 1	297
February	1st to 10th	Day	17% 12% 37% 26% 7%	270
	11th to 20th	Day	21% 13% 37% 23% 6%	270
	21st to end	Day	26% 13% 39% 18% 4	225
March	1st to 10th	Day	19% 14% 34% 26% 6%	270
	11th to 20th	Day	15% 17% 36% 26% 4 2	270
	21st to end	Day	13% 12% 46% 21% 6% 1	297
April	1st to 10th	Day	14% 14% 39% 22% 10%	270
	11th to 20th	Day	15% 9% 45% 23% 8%	332
	21st to end	Day	15% 13% 37% 25% 9% 2	650
May	1st to 10th	Day	14% 9% 36% 32% 9% 1	653
	11th to 20th	Day	15% 6% 27% 34% 15% 3	675
	21st to end	Day	11% 7% 29% 31% 17% 4	734
June	1st to 10th	Day	5% 2 14% 41% 28% 10%	680
	11th to 20th	Day	4 2 17% 44% 27% 6%	680
	21st to end	Day	3 1 10% 36% 37% 12%	680
July	1st to 10th	Day	5% 3 6% 31% 38% 17%	671
	11th to 20th	Day	2 5% 30% 46% 16%	668
	21st to end	Day	3 1 6% 25% 47% 18%	739
August	1st to 10th	Day	2 1 4 28% 47% 18%	676
	11th to 20th	Day	7% 1 5% 27% 45% 15%	622
	21st to end	Day	5% 1 5% 27% 33% 29%	457
September	1st to 10th	Day	9% 1 4 19% 41% 27%	300
	11th to 20th	Day	3 2 5% 23% 45% 23%	300
	21st to end	Day	9% 3 6% 29% 34% 20%	300
October	1st to 10th	Day	3 2 14% 35% 33% 14%	300
	11th to 20th	Day	8% 3 30% 33% 22% 4	300
	21st to end	Day	21% 8% 21% 27% 20% 3	330
November	1st to 10th	Day	18% 5% 34% 27% 12% 4	300
	11th to 20th	Day	11% 9% 30% 29% 17% 4	300
	21st to end	Day	17% 10% 37% 21% 13% 1	300
December	1st to 10th	Day	16% 6% 33% 28% 13% 3	273
	11th to 20th	Day	14% 11% 37% 28% 9% 1	270
	21st to end	Day	20% 9% 35% 24% 11%	297
January	1st to 10th	Night	12% 8% 37% 35% 8%	950
	11th to 20th	Night	15% 11% 32% 36% 6%	950
	21st to end	Night	15% 10% 33% 35% 7%	1045
February	1st to 10th	Night	15% 10% 40% 31% 4	765
	11th to 20th	Night	15% 8% 44% 30% 2	744
	21st to end	Night	18% 13% 44% 22% 2	628
March	1st to 10th	Night	14% 11% 42% 27% 6%	602
	11th to 20th	Night	15% 9% 41% 30% 5%	570
	21st to end	Night	11% 12% 42% 32% 4	627
April	1st to 10th	Night	11% 12% 45% 27% 5%	570
	11th to 20th	Night	12% 12% 45% 26% 5%	563
	21st to end	Night	11% 8% 47% 27% 7%	570
May	1st to 10th	Night	10% 9% 42% 33% 6% 1	570
	11th to 20th	Night	11% 4 33% 38% 13% 1	561
	21st to end	Night	7% 4 33% 40% 15% 1	617
June	1st to 10th	Night	4 2 20% 47% 25% 2	570
	11th to 20th	Night	2 1 24% 58% 14%	570
	21st to end	Night	4 1 14% 49% 29% 3	570
July	1st to 10th	Night	4 1 10% 44% 37% 5%	555
	11th to 20th	Night	2 1 9% 49% 37% 3	552
	21st to end	Night	2 1 4 52% 38% 3	624
August	1st to 10th	Night	2 5% 48% 43% 2	567
	11th to 20th	Night	5% 1 7% 46% 37% 5%	564
	21st to end	Night	4 1 4 44% 42% 5%	627
September	1st to 10th	Night	8% 2 8% 41% 38% 4	570
	11th to 20th	Night	10% 1 8% 42% 38% 1	570
	21st to end	Night	8% 1 13% 45% 30% 3	570
October	1st to 10th	Night	6% 2 21% 43% 27% 3	570
	11th to 20th	Night	11% 5% 27% 40% 16% 1	729
	21st to end	Night	16% 7% 29% 32% 16% 1	836
November	1st to 10th	Night	10% 3 28% 40% 17% 1	780
	11th to 20th	Night	7% 7% 34% 37% 12% 1	1000
	21st to end	Night	17% 8% 35% 29% 10% 1	1000
December	1st to 10th	Night	13% 7% 35% 39% 6%	960
	11th to 20th	Night	17% 7% 35% 34% 7%	950
	21st to end	Night	15% 8% 36% 32% 8%	1045

Page generated at 2024-11-29 09:43:10. Version ac07

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