Bonanza Conservation Area
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Bonanza Conservation Area clear sky chart from 2005-11-06 to 2024-11-01.

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%	101173
	Night	11% 7% 3 7% 4 4 4 3 5% 7% 46%	97871
Transparency	Day	39% 6% 12% 26% 15% 2	100982
	Night	38% 5% 12% 26% 17% 3	97733
Seeing	Day	14% 10% 28% 27% 16% 4	15705
	Night	14% 9% 32% 32% 12% 1	25519

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% 10% 4 10% 5% 4 4 4 5% 7% 33%	2783
	11th to 20th	Day	10% 13% 4 10% 6% 6% 7% 2 3 4 36%	2850
	21st to end	Day	13% 16% 7% 13% 5% 4 4 3 4 5% 26%	3135
February	1st to 10th	Day	14% 10% 5% 8% 4 4 5% 3 6% 7% 34%	1710
	11th to 20th	Day	12% 11% 4 7% 4 3 4 3 5% 7% 40%	1664
	21st to end	Day	12% 10% 3 7% 4 3 3 3 5% 7% 42%	1589
March	1st to 10th	Day	15% 10% 3 6% 4 3 3 3 4 5% 45%	3436
	11th to 20th	Day	11% 7% 2 5% 3 3 3 4 5% 6% 49%	3480
	21st to end	Day	17% 14% 5% 8% 5% 4 4 3 5% 6% 29%	3814
April	1st to 10th	Day	14% 8% 3 7% 4 3 4 3 5% 6% 43%	2236
	11th to 20th	Day	14% 9% 2 7% 5% 4 4 4 5% 7% 40%	2254
	21st to end	Day	20% 8% 3 7% 4 4 5% 4 5% 7% 35%	2376
May	1st to 10th	Day	15% 8% 3 7% 5% 4 5% 4 6% 6% 39%	4082
	11th to 20th	Day	16% 8% 3 7% 5% 4 4 3 5% 7% 38%	4082
	21st to end	Day	12% 6% 2 6% 4 4 4 3 4 7% 46%	4820
June	1st to 10th	Day	7% 4 2 5% 5% 4 5% 4 7% 9% 47%	2660
	11th to 20th	Day	8% 5% 2 6% 5% 4 5% 4 7% 9% 46%	2660
	21st to end	Day	8% 4 2 5% 4 5% 5% 4 7% 9% 48%	2660
July	1st to 10th	Day	11% 7% 3 6% 5% 5% 5% 4 6% 9% 39%	4384
	11th to 20th	Day	6% 5% 2 5% 4 4 4 4 7% 8% 53%	4120
	21st to end	Day	5% 4 2 6% 4 5% 6% 5% 8% 10% 46%	4465
August	1st to 10th	Day	5% 4 1 6% 4 4 5% 4 7% 10% 51%	4104
	11th to 20th	Day	11% 5% 1 5% 4 5% 5% 4 6% 9% 46%	4041
	21st to end	Day	6% 4 2 5% 3 4 4 4 6% 8% 53%	4222
September	1st to 10th	Day	12% 4 2 4 3 3 3 3 4 7% 54%	2280
	11th to 20th	Day	9% 5% 1 5% 4 4 4 4 5% 8% 50%	2176
	21st to end	Day	10% 5% 2 4 4 4 4 3 5% 6% 55%	2040
October	1st to 10th	Day	12% 6% 2 4 3 3 3 3 5% 6% 52%	1900
	11th to 20th	Day	13% 7% 2 4 4 2 4 3 3 4 55%	1900
	21st to end	Day	14% 7% 3 5% 4 4 3 2 5% 6% 47%	2090
November	1st to 10th	Day	9% 6% 2 4 4 3 3 3 6% 6% 53%	1858
	11th to 20th	Day	13% 7% 2 6% 4 3 3 3 5% 6% 49%	1561
	21st to end	Day	16% 11% 3 5% 4 3 2 2 5% 6% 43%	1520
December	1st to 10th	Day	10% 8% 4 7% 5% 5% 4 3 5% 7% 41%	1520
	11th to 20th	Day	12% 10% 4 8% 5% 4 4 3 5% 5% 41%	1918
	21st to end	Day	17% 14% 6% 13% 5% 4 4 4 4 4 24%	2783
January	1st to 10th	Night	9% 9% 4 14% 6% 5% 4 3 5% 5% 35%	4168
	11th to 20th	Night	12% 10% 4 7% 5% 6% 5% 4 7% 5% 34%	4120
	21st to end	Night	15% 11% 6% 13% 4 4 4 3 3 5% 31%	4532
February	1st to 10th	Night	12% 10% 4 8% 5% 4 4 3 5% 6% 38%	2470
	11th to 20th	Night	12% 8% 3 7% 4 4 4 4 5% 6% 42%	2403
	21st to end	Night	13% 8% 3 6% 4 3 3 3 5% 6% 46%	1880
March	1st to 10th	Night	13% 9% 3 6% 4 3 3 3 4 5% 47%	3419
	11th to 20th	Night	11% 7% 2 5% 3 3 3 3 4 6% 54%	3480
	21st to end	Night	16% 10% 4 10% 5% 5% 5% 3 5% 6% 31%	3817
April	1st to 10th	Night	10% 7% 2 6% 4 4 3 3 4 7% 49%	1943
	11th to 20th	Night	13% 8% 2 7% 4 3 4 3 5% 6% 45%	1875
	21st to end	Night	16% 7% 2 7% 4 4 4 3 5% 6% 42%	1800
May	1st to 10th	Night	14% 6% 2 5% 4 4 4 4 6% 8% 41%	2823
	11th to 20th	Night	14% 7% 2 6% 4 4 4 4 5% 8% 41%	2823
	21st to end	Night	11% 5% 2 5% 3 4 4 3 5% 6% 52%	2746
June	1st to 10th	Night	6% 3 1 4 3 3 5% 4 8% 10% 53%	1520
	11th to 20th	Night	4 3 2 5% 5% 4 4 4 7% 11% 50%	1520
	21st to end	Night	5% 4 1 3 3 4 3 3 5% 11% 59%	1520
July	1st to 10th	Night	11% 7% 2 6% 4 4 4 3 6% 7% 47%	2581
	11th to 20th	Night	2 3 1 4 3 4 4 4 5% 9% 61%	2850
	21st to end	Night	5% 4 1 5% 4 5% 4 3 8% 11% 49%	3098
August	1st to 10th	Night	3 2 1 3 3 3 4 4 7% 10% 60%	2836
	11th to 20th	Night	11% 6% 2 5% 4 3 4 2 4 6% 54%	2798
	21st to end	Night	4 3 2 6% 4 3 4 3 5% 8% 59%	3435
September	1st to 10th	Night	9% 5% 1 4 3 3 4 3 4 6% 58%	1900
	11th to 20th	Night	10% 4 1 4 2 3 4 3 7% 8% 54%	2001
	21st to end	Night	7% 5% 2 5% 4 3 3 3 5% 7% 58%	2119
October	1st to 10th	Night	11% 5% 2 4 3 2 3 3 4 6% 57%	2280
	11th to 20th	Night	13% 4 2 5% 4 3 3 2 4 5% 56%	2280
	21st to end	Night	16% 7% 2 5% 3 3 2 2 4 5% 51%	2508
November	1st to 10th	Night	8% 5% 1 4 2 3 3 3 5% 6% 60%	2227
	11th to 20th	Night	12% 6% 2 5% 4 3 3 3 4 5% 53%	2616
	21st to end	Night	15% 9% 2 5% 4 3 3 3 4 5% 48%	2660
December	1st to 10th	Night	11% 8% 3 6% 4 5% 4 4 5% 6% 43%	2660
	11th to 20th	Night	12% 9% 3 7% 4 3 3 3 5% 6% 44%	3279
	21st to end	Night	19% 17% 6% 11% 4 3 3 2 4 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	49% 5% 13% 23% 9% 1	2784
	11th to 20th	Day	54% 4 13% 19% 10%	2850
	21st to end	Day	60% 4 10% 15% 9% 1	3135
February	1st to 10th	Day	49% 5% 13% 20% 10% 3	1710
	11th to 20th	Day	44% 5% 12% 23% 14% 2	1673
	21st to end	Day	42% 5% 11% 21% 18% 3	1589
March	1st to 10th	Day	42% 4 10% 21% 21% 2	3436
	11th to 20th	Day	35% 5% 11% 28% 18% 3	3480
	21st to end	Day	55% 7% 14% 19% 5% 1	3814
April	1st to 10th	Day	42% 6% 11% 25% 15% 2	2236
	11th to 20th	Day	44% 5% 12% 23% 15% 1	2254
	21st to end	Day	49% 6% 11% 23% 11% 1	2376
May	1st to 10th	Day	44% 7% 11% 23% 14% 1	4120
	11th to 20th	Day	45% 7% 12% 24% 12%	4086
	21st to end	Day	37% 6% 10% 29% 16% 2	4833
June	1st to 10th	Day	31% 9% 15% 30% 14% 2	2660
	11th to 20th	Day	32% 7% 14% 27% 18% 1	2660
	21st to end	Day	31% 7% 16% 28% 14% 3	2660
July	1st to 10th	Day	41% 6% 13% 24% 12% 3	4316
	11th to 20th	Day	28% 6% 11% 35% 18% 2	4051
	21st to end	Day	30% 7% 17% 30% 13% 2	4325
August	1st to 10th	Day	27% 6% 15% 31% 20% 1	4090
	11th to 20th	Day	35% 5% 15% 28% 16% 1	4080
	21st to end	Day	27% 6% 16% 31% 13% 6%	4221
September	1st to 10th	Day	30% 6% 11% 27% 20% 6%	2280
	11th to 20th	Day	31% 6% 12% 26% 22% 2	2176
	21st to end	Day	31% 5% 8% 31% 22% 3	2040
October	1st to 10th	Day	33% 5% 11% 27% 22% 2	1900
	11th to 20th	Day	34% 3 7% 26% 23% 6%	1900
	21st to end	Day	39% 4 11% 23% 19% 4	2090
November	1st to 10th	Day	31% 4 14% 27% 19% 4	1858
	11th to 20th	Day	36% 4 11% 27% 19% 2	1561
	21st to end	Day	43% 3 9% 27% 17%	1520
December	1st to 10th	Day	42% 6% 13% 25% 14% 1	1520
	11th to 20th	Day	45% 5% 14% 27% 8% 1	1915
	21st to end	Day	63% 4 10% 14% 7% 1	2783
January	1st to 10th	Night	50% 5% 11% 22% 11% 1	4168
	11th to 20th	Night	50% 4 12% 21% 12% 1	4120
	21st to end	Night	56% 4 13% 17% 9% 1	4532
February	1st to 10th	Night	47% 6% 11% 20% 14% 3	2470
	11th to 20th	Night	43% 5% 11% 22% 16% 3	2404
	21st to end	Night	40% 4 10% 22% 19% 5%	1880
March	1st to 10th	Night	40% 4 10% 24% 19% 3	3419
	11th to 20th	Night	32% 4 8% 29% 22% 5%	3480
	21st to end	Night	52% 7% 14% 20% 6% 1	3817
April	1st to 10th	Night	36% 4 10% 27% 19% 4	1943
	11th to 20th	Night	40% 5% 9% 27% 15% 3	1875
	21st to end	Night	43% 5% 10% 25% 16% 1	1800
May	1st to 10th	Night	39% 9% 13% 22% 16% 1	2850
	11th to 20th	Night	40% 8% 11% 29% 12% 1	2824
	21st to end	Night	33% 6% 11% 27% 22% 2	2754
June	1st to 10th	Night	23% 8% 17% 32% 16% 3	1520
	11th to 20th	Night	27% 7% 13% 29% 20% 3	1520
	21st to end	Night	21% 6% 15% 34% 20% 4	1520
July	1st to 10th	Night	36% 5% 11% 24% 20% 3	2540
	11th to 20th	Night	19% 6% 15% 37% 21% 2	2796
	21st to end	Night	28% 6% 21% 32% 13% 1	2999
August	1st to 10th	Night	18% 5% 20% 30% 26% 2	2826
	11th to 20th	Night	33% 4 12% 28% 22% 1	2825
	21st to end	Night	25% 4 16% 34% 17% 5%	3435
September	1st to 10th	Night	28% 5% 9% 27% 24% 8%	1900
	11th to 20th	Night	26% 5% 11% 29% 24% 4	2001
	21st to end	Night	27% 5% 8% 30% 26% 4	2119
October	1st to 10th	Night	29% 5% 9% 25% 27% 5%	2280
	11th to 20th	Night	32% 3 8% 25% 23% 8%	2280
	21st to end	Night	38% 3 8% 23% 23% 3	2508
November	1st to 10th	Night	26% 5% 15% 26% 23% 6%	2227
	11th to 20th	Night	33% 4 8% 29% 21% 4	2616
	21st to end	Night	40% 3 10% 27% 17% 3	2660
December	1st to 10th	Night	41% 5% 12% 27% 14% 1	2660
	11th to 20th	Night	41% 5% 11% 30% 12% 1	3281
	21st to end	Night	62% 4 7% 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	21% 15% 36% 21% 6%	270
	11th to 20th	Day	26% 15% 40% 17% 2	270
	21st to end	Day	15% 16% 44% 21% 3	297
February	1st to 10th	Day	21% 22% 39% 15% 3	270
	11th to 20th	Day	18% 17% 43% 14% 8%	270
	21st to end	Day	16% 22% 39% 19% 4	225
March	1st to 10th	Day	19% 17% 45% 17% 3	270
	11th to 20th	Day	27% 15% 33% 20% 4	270
	21st to end	Day	40% 15% 28% 14% 2	297
April	1st to 10th	Day	21% 17% 36% 19% 7%	416
	11th to 20th	Day	18% 16% 37% 22% 6% 1	452
	21st to end	Day	23% 17% 33% 19% 8% 1	556
May	1st to 10th	Day	18% 14% 36% 23% 8% 1	653
	11th to 20th	Day	20% 12% 28% 27% 12% 2	675
	21st to end	Day	16% 7% 30% 26% 18% 3	734
June	1st to 10th	Day	6% 4 21% 36% 24% 8%	680
	11th to 20th	Day	8% 5% 25% 37% 20% 5%	680
	21st to end	Day	7% 6% 35% 33% 16% 2	680
July	1st to 10th	Day	10% 3 17% 31% 29% 12%	671
	11th to 20th	Day	6% 3 21% 36% 26% 8%	668
	21st to end	Day	6% 2 17% 38% 29% 7%	739
August	1st to 10th	Day	7% 2 20% 37% 27% 7%	676
	11th to 20th	Day	9% 4 18% 34% 29% 7%	665
	21st to end	Day	9% 2 14% 31% 32% 12%	568
September	1st to 10th	Day	13% 3 14% 33% 29% 7%	490
	11th to 20th	Day	8% 4 18% 36% 26% 8%	386
	21st to end	Day	12% 8% 27% 28% 20% 6%	300
October	1st to 10th	Day	16% 7% 26% 28% 16% 7%	300
	11th to 20th	Day	11% 23% 35% 22% 8% 1	300
	21st to end	Day	20% 16% 35% 22% 6%	330
November	1st to 10th	Day	15% 9% 42% 24% 7% 3	270
	11th to 20th	Day	16% 19% 33% 24% 5% 3	270
	21st to end	Day	23% 16% 27% 26% 7%	270
December	1st to 10th	Day	11% 19% 36% 23% 7% 3	270
	11th to 20th	Day	21% 16% 35% 22% 5% 1	270
	21st to end	Day	21% 23% 37% 18% 1	297
January	1st to 10th	Night	14% 13% 39% 26% 7%	950
	11th to 20th	Night	16% 15% 39% 22% 7% 1	950
	21st to end	Night	17% 12% 39% 29% 3	1045
February	1st to 10th	Night	17% 11% 44% 24% 4	950
	11th to 20th	Night	16% 14% 38% 28% 4	929
	21st to end	Night	19% 16% 43% 17% 5% 1	624
March	1st to 10th	Night	18% 12% 39% 26% 5%	570
	11th to 20th	Night	20% 10% 35% 28% 6% 1	570
	21st to end	Night	27% 11% 36% 21% 5%	627
April	1st to 10th	Night	13% 13% 42% 27% 4	570
	11th to 20th	Night	18% 14% 35% 26% 7%	563
	21st to end	Night	19% 11% 36% 27% 6% 1	570
May	1st to 10th	Night	16% 10% 36% 30% 7% 1	570
	11th to 20th	Night	18% 7% 26% 34% 14% 1	561
	21st to end	Night	12% 6% 27% 37% 16% 2	617
June	1st to 10th	Night	6% 3 22% 45% 21% 3	570
	11th to 20th	Night	6% 3 25% 48% 17% 2	570
	21st to end	Night	5% 3 28% 47% 16%	570
July	1st to 10th	Night	8% 2 13% 41% 32% 4	555
	11th to 20th	Night	3 2 16% 48% 30% 2	552
	21st to end	Night	6% 2 13% 42% 34% 3	624
August	1st to 10th	Night	4 1 16% 47% 29% 1	567
	11th to 20th	Night	7% 2 14% 43% 31% 3	564
	21st to end	Night	6% 2 14% 42% 33% 3	627
September	1st to 10th	Night	11% 2 17% 38% 27% 4	570
	11th to 20th	Night	12% 2 19% 39% 25% 4	570
	21st to end	Night	9% 5% 23% 39% 21% 3	599
October	1st to 10th	Night	13% 5% 28% 35% 17% 2	760
	11th to 20th	Night	15% 9% 35% 30% 10%	760
	21st to end	Night	20% 11% 33% 28% 7%	836
November	1st to 10th	Night	11% 10% 35% 34% 9% 1	743
	11th to 20th	Night	14% 13% 38% 26% 8%	921
	21st to end	Night	19% 11% 36% 27% 7%	950
December	1st to 10th	Night	17% 13% 36% 26% 7% 1	950
	11th to 20th	Night	19% 10% 39% 27% 6%	950
	21st to end	Night	21% 16% 34% 26% 3	1045

Page generated at 2024-10-29 10:20:44. Version ac07

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