Cameron
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cameron clear sky chart from 2005-11-06 to 2024-11-03.

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	11% 8% 3 7% 4 4 4 4 5% 7% 43%	101181
	Night	11% 7% 3 7% 4 4 4 3 5% 7% 46%	97898
Transparency	Day	39% 6% 13% 25% 15% 2	100991
	Night	38% 5% 12% 26% 17% 3	97759
Seeing	Day	14% 10% 29% 28% 15% 4	15720
	Night	14% 9% 32% 32% 11% 1	25537

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	13% 11% 4 10% 5% 3 4 4 6% 8% 33%	2815
	11th to 20th	Day	10% 13% 5% 10% 5% 6% 7% 2 3 5% 35%	2850
	21st to end	Day	13% 15% 7% 14% 5% 5% 4 3 4 5% 26%	3135
February	1st to 10th	Day	14% 10% 5% 7% 5% 5% 5% 3 6% 5% 34%	1710
	11th to 20th	Day	11% 11% 4 7% 5% 3 4 2 5% 7% 41%	1664
	21st to end	Day	11% 10% 4 8% 4 4 4 3 5% 7% 42%	1589
March	1st to 10th	Day	15% 10% 2 6% 4 3 4 3 4 4 45%	3436
	11th to 20th	Day	10% 8% 3 6% 3 4 4 3 5% 7% 49%	3480
	21st to end	Day	17% 13% 5% 8% 5% 4 4 4 5% 6% 29%	3814
April	1st to 10th	Day	14% 8% 3 6% 5% 4 3 4 4 6% 43%	2223
	11th to 20th	Day	14% 8% 3 7% 4 4 5% 3 5% 7% 40%	2254
	21st to end	Day	21% 7% 2 8% 4 5% 4 3 5% 6% 35%	2403
May	1st to 10th	Day	15% 8% 3 6% 4 4 4 4 6% 7% 39%	4082
	11th to 20th	Day	16% 8% 3 7% 5% 4 4 3 5% 8% 38%	4082
	21st to end	Day	12% 6% 2 6% 4 5% 3 4 5% 7% 46%	4784
June	1st to 10th	Day	6% 5% 2 5% 5% 5% 5% 5% 7% 9% 47%	2660
	11th to 20th	Day	7% 6% 2 5% 5% 4 5% 4 8% 8% 46%	2660
	21st to end	Day	8% 4 2 5% 5% 4 5% 4 6% 9% 48%	2660
July	1st to 10th	Day	10% 7% 3 7% 4 5% 5% 5% 6% 8% 40%	4347
	11th to 20th	Day	7% 4 1 5% 4 3 4 4 6% 8% 54%	4120
	21st to end	Day	5% 3 2 6% 4 5% 5% 5% 7% 11% 47%	4465
August	1st to 10th	Day	5% 4 2 5% 4 4 4 4 7% 9% 50%	4104
	11th to 20th	Day	11% 5% 2 5% 4 4 4 4 6% 8% 46%	4041
	21st to end	Day	6% 4 2 5% 3 4 4 3 7% 9% 53%	4254
September	1st to 10th	Day	11% 5% 1 3 3 4 4 3 5% 7% 54%	2280
	11th to 20th	Day	9% 5% 2 5% 4 4 4 4 6% 8% 50%	2152
	21st to end	Day	9% 4 2 5% 4 3 4 3 4 5% 56%	2052
October	1st to 10th	Day	12% 7% 2 4 4 4 3 2 5% 6% 52%	1900
	11th to 20th	Day	13% 6% 2 5% 3 3 3 2 4 4 54%	1900
	21st to end	Day	14% 8% 3 6% 3 4 4 2 5% 6% 47%	2090
November	1st to 10th	Day	9% 6% 2 5% 3 3 3 4 6% 7% 53%	1878
	11th to 20th	Day	13% 6% 3 5% 5% 3 3 3 5% 7% 48%	1556
	21st to end	Day	16% 10% 3 5% 3 3 3 2 5% 6% 43%	1520
December	1st to 10th	Day	9% 9% 3 8% 5% 4 4 4 6% 8% 41%	1520
	11th to 20th	Day	12% 10% 3 8% 5% 5% 4 4 4 6% 40%	1918
	21st to end	Day	17% 14% 7% 14% 4 4 4 4 4 5% 24%	2783
January	1st to 10th	Night	9% 9% 4 14% 7% 6% 4 3 5% 5% 34%	4136
	11th to 20th	Night	11% 10% 5% 8% 5% 5% 6% 5% 6% 5% 34%	4120
	21st to end	Night	14% 12% 5% 13% 4 4 5% 3 4 5% 31%	4532
February	1st to 10th	Night	11% 12% 4 8% 5% 5% 4 3 5% 5% 37%	2470
	11th to 20th	Night	12% 8% 3 8% 4 4 4 3 5% 7% 42%	2403
	21st to end	Night	12% 9% 3 5% 4 3 3 3 5% 5% 47%	1880
March	1st to 10th	Night	13% 7% 3 6% 4 3 4 3 4 4 48%	3419
	11th to 20th	Night	11% 7% 2 5% 3 3 3 2 4 5% 54%	3480
	21st to end	Night	16% 9% 4 11% 5% 4 5% 4 5% 5% 31%	3817
April	1st to 10th	Night	10% 6% 2 7% 3 3 4 3 5% 7% 49%	1957
	11th to 20th	Night	13% 7% 3 6% 4 4 4 3 5% 6% 45%	1875
	21st to end	Night	15% 8% 3 6% 3 3 4 3 5% 6% 42%	1775
May	1st to 10th	Night	14% 6% 2 6% 4 4 4 4 6% 9% 41%	2823
	11th to 20th	Night	14% 8% 2 6% 4 3 4 3 6% 7% 42%	2823
	21st to end	Night	12% 5% 2 5% 4 3 4 3 4 7% 52%	2778
June	1st to 10th	Night	5% 3 1 4 3 4 5% 4 7% 9% 54%	1520
	11th to 20th	Night	4 4 2 4 4 5% 5% 4 8% 10% 51%	1520
	21st to end	Night	5% 3 1 4 3 3 3 3 5% 11% 59%	1520
July	1st to 10th	Night	10% 7% 3 6% 3 4 3 4 4 7% 48%	2617
	11th to 20th	Night	3 3 1 4 3 4 4 3 6% 8% 62%	2850
	21st to end	Night	5% 4 1 5% 4 4 5% 4 8% 11% 48%	3098
August	1st to 10th	Night	3 2 1 2 3 3 4 4 6% 10% 61%	2836
	11th to 20th	Night	11% 7% 2 5% 4 3 3 3 4 7% 53%	2798
	21st to end	Night	5% 3 2 5% 4 3 4 3 5% 8% 58%	3404
September	1st to 10th	Night	9% 4 1 4 3 3 4 3 5% 7% 57%	1900
	11th to 20th	Night	9% 4 1 5% 3 4 4 4 5% 7% 55%	2023
	21st to end	Night	7% 4 2 4 4 3 3 3 4 7% 58%	2107
October	1st to 10th	Night	10% 6% 2 4 3 3 2 3 4 6% 56%	2280
	11th to 20th	Night	13% 5% 1 4 4 3 3 3 4 6% 56%	2280
	21st to end	Night	16% 7% 2 5% 4 3 3 2 3 5% 51%	2508
November	1st to 10th	Night	8% 4 2 4 2 3 3 3 4 6% 61%	2245
	11th to 20th	Night	11% 7% 2 5% 4 3 3 3 4 5% 52%	2621
	21st to end	Night	14% 9% 2 6% 3 3 2 3 5% 5% 48%	2660
December	1st to 10th	Night	11% 9% 3 6% 5% 4 5% 4 5% 6% 43%	2660
	11th to 20th	Night	12% 9% 3 8% 3 3 3 3 4 6% 45%	3279
	21st to end	Night	19% 17% 7% 11% 4 3 3 2 3 4 27%	4884

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	48% 6% 14% 22% 10% 1	2816
	11th to 20th	Day	54% 4 13% 19% 10%	2850
	21st to end	Day	60% 5% 10% 16% 8% 1	3135
February	1st to 10th	Day	50% 5% 12% 20% 10% 3	1710
	11th to 20th	Day	44% 4 12% 24% 14% 2	1673
	21st to end	Day	42% 5% 11% 22% 18% 3	1589
March	1st to 10th	Day	41% 5% 11% 21% 21% 1	3436
	11th to 20th	Day	34% 6% 11% 27% 19% 2	3480
	21st to end	Day	53% 8% 15% 18% 5% 1	3814
April	1st to 10th	Day	42% 5% 12% 25% 14% 2	2223
	11th to 20th	Day	43% 5% 13% 23% 15% 1	2254
	21st to end	Day	49% 6% 11% 22% 11% 1	2403
May	1st to 10th	Day	43% 8% 12% 22% 14% 1	4120
	11th to 20th	Day	44% 7% 12% 25% 12%	4086
	21st to end	Day	37% 7% 11% 28% 16% 2	4797
June	1st to 10th	Day	30% 10% 15% 30% 14% 2	2660
	11th to 20th	Day	32% 7% 15% 27% 18% 1	2660
	21st to end	Day	30% 7% 17% 28% 15% 3	2660
July	1st to 10th	Day	40% 6% 14% 25% 12% 3	4280
	11th to 20th	Day	28% 5% 11% 35% 19% 2	4051
	21st to end	Day	28% 7% 17% 31% 14% 2	4325
August	1st to 10th	Day	28% 6% 16% 30% 19% 1	4090
	11th to 20th	Day	35% 6% 15% 28% 16% 1	4080
	21st to end	Day	27% 7% 17% 30% 14% 5%	4253
September	1st to 10th	Day	30% 6% 11% 28% 20% 5%	2280
	11th to 20th	Day	32% 6% 13% 27% 21% 2	2152
	21st to end	Day	30% 5% 8% 32% 22% 3	2052
October	1st to 10th	Day	33% 5% 11% 27% 22% 2	1900
	11th to 20th	Day	34% 4 7% 27% 23% 6%	1900
	21st to end	Day	39% 4 11% 23% 18% 5%	2090
November	1st to 10th	Day	30% 5% 14% 27% 20% 4	1878
	11th to 20th	Day	36% 5% 11% 27% 19% 2	1556
	21st to end	Day	42% 5% 10% 26% 17%	1520
December	1st to 10th	Day	41% 7% 13% 24% 14% 1	1520
	11th to 20th	Day	45% 6% 15% 27% 7% 1	1915
	21st to end	Day	63% 4 10% 15% 6% 1	2783
January	1st to 10th	Night	50% 6% 11% 21% 11% 1	4136
	11th to 20th	Night	49% 5% 12% 21% 12% 1	4120
	21st to end	Night	55% 5% 13% 16% 8% 1	4532
February	1st to 10th	Night	48% 4 12% 19% 13% 3	2470
	11th to 20th	Night	42% 4 13% 22% 16% 3	2404
	21st to end	Night	38% 5% 11% 23% 18% 6%	1880
March	1st to 10th	Night	39% 4 11% 23% 20% 2	3419
	11th to 20th	Night	32% 5% 8% 29% 21% 5%	3480
	21st to end	Night	51% 8% 15% 19% 5% 1	3817
April	1st to 10th	Night	35% 5% 10% 28% 18% 4	1957
	11th to 20th	Night	39% 5% 11% 28% 14% 3	1875
	21st to end	Night	41% 5% 11% 26% 16% 1	1775
May	1st to 10th	Night	38% 8% 13% 22% 17% 1	2850
	11th to 20th	Night	39% 7% 11% 29% 13% 1	2824
	21st to end	Night	33% 6% 12% 26% 22% 1	2786
June	1st to 10th	Night	24% 8% 17% 32% 16% 3	1520
	11th to 20th	Night	26% 8% 15% 29% 19% 3	1520
	21st to end	Night	21% 5% 17% 34% 20% 4	1520
July	1st to 10th	Night	36% 4 13% 24% 19% 4	2575
	11th to 20th	Night	18% 6% 16% 36% 21% 2	2796
	21st to end	Night	27% 7% 19% 33% 13% 1	2999
August	1st to 10th	Night	18% 5% 20% 29% 26% 2	2826
	11th to 20th	Night	33% 4 12% 28% 22% 1	2825
	21st to end	Night	25% 5% 15% 33% 17% 5%	3404
September	1st to 10th	Night	28% 5% 11% 26% 23% 8%	1900
	11th to 20th	Night	27% 5% 12% 29% 24% 3	2023
	21st to end	Night	28% 4 8% 30% 27% 4	2107
October	1st to 10th	Night	30% 4 9% 25% 26% 5%	2280
	11th to 20th	Night	32% 3 7% 27% 23% 8%	2280
	21st to end	Night	38% 3 9% 23% 23% 3	2508
November	1st to 10th	Night	25% 5% 14% 28% 22% 6%	2245
	11th to 20th	Night	34% 4 9% 29% 20% 4	2621
	21st to end	Night	39% 4 11% 27% 17% 3	2660
December	1st to 10th	Night	40% 6% 12% 27% 14% 1	2660
	11th to 20th	Night	41% 4 12% 30% 12% 1	3281
	21st to end	Night	63% 4 6% 17% 8% 1	4884

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	20% 17% 34% 23% 6%	270
	11th to 20th	Day	25% 13% 45% 15% 1	270
	21st to end	Day	15% 16% 43% 23% 3	297
February	1st to 10th	Day	21% 21% 40% 17% 2	270
	11th to 20th	Day	18% 18% 44% 13% 6% 1	270
	21st to end	Day	16% 22% 44% 17% 2	225
March	1st to 10th	Day	19% 15% 47% 17% 2	270
	11th to 20th	Day	28% 13% 34% 21% 4	270
	21st to end	Day	37% 18% 28% 15% 2	297
April	1st to 10th	Day	22% 14% 37% 20% 6%	403
	11th to 20th	Day	17% 15% 38% 22% 6% 1	452
	21st to end	Day	24% 14% 35% 18% 7% 1	583
May	1st to 10th	Day	19% 12% 37% 23% 8% 1	653
	11th to 20th	Day	20% 10% 31% 25% 12% 2	675
	21st to end	Day	17% 8% 28% 26% 17% 3	734
June	1st to 10th	Day	6% 5% 22% 36% 24% 8%	680
	11th to 20th	Day	8% 5% 26% 39% 18% 4	680
	21st to end	Day	7% 7% 34% 37% 13% 2	680
July	1st to 10th	Day	9% 5% 15% 32% 30% 9%	671
	11th to 20th	Day	7% 4 23% 34% 24% 8%	668
	21st to end	Day	7% 2 16% 40% 29% 6%	739
August	1st to 10th	Day	7% 2 18% 39% 27% 6%	676
	11th to 20th	Day	9% 4 19% 35% 26% 7%	665
	21st to end	Day	10% 2 15% 36% 27% 11%	587
September	1st to 10th	Day	12% 2 17% 32% 30% 7%	490
	11th to 20th	Day	10% 2 18% 37% 27% 6%	362
	21st to end	Day	13% 9% 26% 31% 16% 5%	300
October	1st to 10th	Day	17% 6% 26% 30% 15% 6%	300
	11th to 20th	Day	13% 23% 34% 22% 7% 1	300
	21st to end	Day	18% 17% 36% 22% 7% 1	330
November	1st to 10th	Day	15% 9% 40% 26% 7% 3	276
	11th to 20th	Day	17% 18% 34% 23% 5% 3	270
	21st to end	Day	21% 15% 34% 23% 6% 1	270
December	1st to 10th	Day	11% 18% 37% 26% 6% 2	270
	11th to 20th	Day	21% 14% 35% 23% 6% 1	270
	21st to end	Day	21% 21% 39% 18% 1	297
January	1st to 10th	Night	13% 14% 41% 26% 6%	950
	11th to 20th	Night	16% 14% 41% 23% 6% 1	950
	21st to end	Night	16% 13% 40% 27% 4	1045
February	1st to 10th	Night	16% 14% 42% 25% 3	950
	11th to 20th	Night	16% 14% 37% 28% 4	929
	21st to end	Night	18% 16% 44% 18% 4	624
March	1st to 10th	Night	14% 14% 41% 25% 6%	570
	11th to 20th	Night	19% 10% 37% 26% 6% 1	570
	21st to end	Night	26% 10% 38% 21% 4	627
April	1st to 10th	Night	13% 15% 40% 28% 4	570
	11th to 20th	Night	18% 12% 38% 25% 6%	563
	21st to end	Night	20% 10% 37% 26% 6% 1	570
May	1st to 10th	Night	18% 10% 35% 30% 7% 1	570
	11th to 20th	Night	17% 7% 30% 34% 12% 1	561
	21st to end	Night	12% 5% 30% 36% 15% 2	617
June	1st to 10th	Night	6% 4 22% 46% 19% 3	570
	11th to 20th	Night	5% 3 27% 46% 17% 2	570
	21st to end	Night	6% 4 28% 50% 13%	570
July	1st to 10th	Night	8% 2 13% 43% 32% 3	555
	11th to 20th	Night	4 3 16% 49% 26% 2	552
	21st to end	Night	7% 1 13% 45% 32% 2	624
August	1st to 10th	Night	5% 2 17% 49% 26% 1	567
	11th to 20th	Night	7% 2 16% 44% 29% 2	564
	21st to end	Night	7% 2 13% 45% 30% 3	627
September	1st to 10th	Night	10% 3 18% 40% 25% 4	570
	11th to 20th	Night	11% 2 20% 43% 22% 2	570
	21st to end	Night	8% 5% 25% 41% 20% 2	587
October	1st to 10th	Night	13% 5% 30% 33% 17% 2	760
	11th to 20th	Night	15% 9% 36% 31% 9%	760
	21st to end	Night	20% 11% 34% 27% 7%	836
November	1st to 10th	Night	10% 11% 35% 34% 9% 1	749
	11th to 20th	Night	14% 15% 39% 25% 8%	945
	21st to end	Night	18% 11% 35% 29% 6%	950
December	1st to 10th	Night	16% 12% 37% 27% 7% 1	950
	11th to 20th	Night	20% 8% 39% 27% 6%	950
	21st to end	Night	20% 15% 37% 25% 3	1045

Page generated at 2024-10-31 02:39:22. Version ac07

Copyright © 2024 Attilla Danko.