Cherry Grove
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cherry Grove clear sky chart from 2005-11-06 to 2024-11-04.

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	13% 9% 3 8% 5% 4 5% 4 6% 7% 37%	101565
	Night	12% 9% 3 8% 5% 4 4 3 5% 6% 39%	97548
Transparency	Day	45% 4 12% 26% 12% 1	105172
	Night	45% 3 12% 25% 14% 2	102082
Seeing	Day	17% 9% 31% 27% 13% 4	15984
	Night	16% 9% 33% 30% 11% 1	25835

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	9% 15% 7% 20% 7% 6% 6% 4 5% 6% 17%	2527
	11th to 20th	Day	6% 13% 5% 12% 10% 8% 7% 6% 9% 6% 18%	2566
	21st to end	Day	10% 18% 7% 16% 7% 4 4 3 5% 6% 18%	3135
February	1st to 10th	Day	8% 12% 4 12% 8% 7% 6% 5% 7% 7% 25%	1710
	11th to 20th	Day	9% 11% 5% 10% 6% 6% 5% 4 6% 6% 31%	1664
	21st to end	Day	13% 10% 4 11% 5% 6% 5% 5% 5% 6% 30%	1498
March	1st to 10th	Day	13% 8% 3 7% 5% 3 3 3 5% 7% 42%	3339
	11th to 20th	Day	11% 9% 3 8% 4 4 4 4 5% 8% 40%	3480
	21st to end	Day	24% 12% 4 11% 5% 5% 4 3 4 5% 22%	3873
April	1st to 10th	Day	18% 11% 4 8% 5% 4 4 3 5% 8% 31%	2280
	11th to 20th	Day	19% 12% 4 7% 4 4 4 4 5% 5% 32%	2254
	21st to end	Day	21% 12% 3 7% 5% 4 4 4 5% 6% 29%	2436
May	1st to 10th	Day	18% 6% 3 6% 4 4 5% 4 6% 8% 36%	4259
	11th to 20th	Day	13% 7% 2 6% 4 4 4 4 6% 8% 42%	4399
	21st to end	Day	18% 7% 2 7% 5% 4 4 4 5% 7% 38%	4824
June	1st to 10th	Day	11% 5% 2 6% 5% 4 4 5% 6% 7% 46%	2660
	11th to 20th	Day	13% 6% 2 7% 5% 5% 4 5% 7% 9% 38%	2660
	21st to end	Day	12% 6% 2 6% 5% 5% 5% 4 6% 9% 40%	2660
July	1st to 10th	Day	10% 5% 3 7% 5% 5% 6% 5% 7% 9% 38%	4440
	11th to 20th	Day	5% 3 1 5% 4 3 4 3 5% 8% 58%	4440
	21st to end	Day	6% 5% 2 6% 5% 5% 5% 5% 7% 8% 46%	4737
August	1st to 10th	Day	11% 6% 2 7% 4 5% 6% 4 6% 7% 42%	4104
	11th to 20th	Day	12% 6% 2 6% 4 4 5% 4 6% 9% 43%	4041
	21st to end	Day	8% 6% 2 6% 4 5% 4 5% 5% 8% 47%	4281
September	1st to 10th	Day	13% 5% 2 5% 4 3 4 4 5% 8% 47%	2280
	11th to 20th	Day	11% 6% 2 7% 4 4 4 4 6% 6% 48%	2275
	21st to end	Day	12% 7% 3 7% 4 4 4 4 4 8% 43%	1983
October	1st to 10th	Day	15% 8% 2 5% 4 3 4 4 5% 6% 45%	1900
	11th to 20th	Day	14% 10% 2 6% 4 4 4 3 5% 6% 42%	1900
	21st to end	Day	17% 11% 4 7% 3 3 4 3 5% 6% 36%	2066
November	1st to 10th	Day	11% 10% 4 8% 3 4 4 4 6% 7% 39%	1633
	11th to 20th	Day	12% 12% 6% 11% 6% 4 4 5% 5% 6% 28%	1520
	21st to end	Day	12% 11% 5% 7% 6% 5% 4 3 4 7% 36%	1520
December	1st to 10th	Day	12% 11% 4 13% 8% 7% 5% 4 5% 6% 26%	1520
	11th to 20th	Day	9% 13% 5% 11% 6% 6% 5% 4 6% 7% 27%	1918
	21st to end	Day	18% 16% 7% 18% 5% 3 4 3 4 5% 16%	2783
January	1st to 10th	Night	9% 15% 7% 18% 6% 5% 4 3 5% 4 25%	4428
	11th to 20th	Night	7% 12% 5% 13% 8% 6% 7% 6% 10% 6% 19%	4399
	21st to end	Night	12% 16% 7% 13% 6% 5% 4 3 4 6% 24%	4532
February	1st to 10th	Night	7% 13% 5% 11% 6% 7% 4 4 5% 6% 33%	2470
	11th to 20th	Night	7% 10% 3 9% 6% 6% 5% 4 6% 6% 38%	2403
	21st to end	Night	13% 9% 4 9% 5% 6% 4 3 5% 5% 35%	1955
March	1st to 10th	Night	11% 8% 3 6% 4 3 4 3 5% 6% 47%	3543
	11th to 20th	Night	9% 7% 3 8% 5% 4 5% 3 7% 8% 41%	3480
	21st to end	Night	24% 12% 4 10% 4 3 3 3 4 5% 29%	3756
April	1st to 10th	Night	15% 12% 3 7% 5% 4 4 4 5% 6% 36%	1900
	11th to 20th	Night	19% 11% 3 7% 4 3 3 3 5% 6% 36%	1875
	21st to end	Night	19% 10% 3 6% 5% 4 3 3 5% 6% 38%	1742
May	1st to 10th	Night	15% 7% 3 6% 5% 4 4 4 4 6% 42%	2645
	11th to 20th	Night	13% 5% 2 4 3 3 3 4 6% 7% 49%	2506
	21st to end	Night	11% 8% 3 7% 5% 4 4 3 5% 6% 44%	2743
June	1st to 10th	Night	9% 4 2 5% 4 4 5% 5% 6% 8% 49%	1520
	11th to 20th	Night	11% 6% 2 6% 4 5% 4 4 6% 8% 44%	1520
	21st to end	Night	9% 4 1 5% 3 4 4 4 5% 8% 53%	1520
July	1st to 10th	Night	10% 4 2 6% 3 4 5% 5% 6% 9% 46%	2530
	11th to 20th	Night	3 3 1 4 3 4 4 4 6% 9% 58%	2530
	21st to end	Night	5% 4 1 5% 3 3 4 3 6% 9% 56%	2811
August	1st to 10th	Night	12% 6% 2 6% 4 4 4 3 5% 7% 47%	2836
	11th to 20th	Night	12% 5% 2 5% 3 3 3 3 5% 6% 52%	2798
	21st to end	Night	8% 6% 3 6% 4 4 4 3 5% 7% 50%	3378
September	1st to 10th	Night	8% 4 2 5% 3 3 3 3 5% 6% 57%	1900
	11th to 20th	Night	11% 5% 2 5% 3 3 4 3 5% 7% 53%	1900
	21st to end	Night	12% 6% 1 5% 3 3 3 3 5% 6% 53%	2177
October	1st to 10th	Night	14% 6% 2 5% 3 3 3 3 5% 6% 50%	2280
	11th to 20th	Night	15% 7% 2 5% 4 4 4 3 5% 8% 43%	2280
	21st to end	Night	16% 10% 3 7% 4 4 4 3 5% 6% 38%	2532
November	1st to 10th	Night	11% 8% 3 7% 4 3 4 4 6% 6% 44%	2516
	11th to 20th	Night	11% 11% 4 10% 5% 5% 4 3 5% 6% 35%	2660
	21st to end	Night	14% 10% 4 8% 5% 4 4 3 5% 6% 38%	2660
December	1st to 10th	Night	10% 11% 5% 11% 7% 6% 5% 4 6% 7% 29%	2660
	11th to 20th	Night	11% 11% 5% 12% 8% 6% 5% 4 5% 6% 28%	3279
	21st to end	Night	20% 15% 5% 14% 6% 5% 4 3 5% 4 19%	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	68% 2 10% 15% 5%	2528
	11th to 20th	Day	63% 2 10% 17% 7%	2566
	21st to end	Day	67% 3 11% 14% 5%	3135
February	1st to 10th	Day	56% 4 12% 17% 10% 1	1710
	11th to 20th	Day	54% 3 11% 24% 7% 2	1673
	21st to end	Day	55% 3 12% 19% 11% 1	1498
March	1st to 10th	Day	43% 2 13% 27% 14% 1	3339
	11th to 20th	Day	42% 4 9% 32% 11% 2	3480
	21st to end	Day	66% 2 9% 17% 5%	3873
April	1st to 10th	Day	53% 3 10% 22% 11% 1	2280
	11th to 20th	Day	54% 4 10% 20% 11% 1	2254
	21st to end	Day	56% 3 12% 20% 8% 1	2436
May	1st to 10th	Day	46% 4 11% 26% 12% 1	4297
	11th to 20th	Day	40% 3 10% 32% 13% 2	4403
	21st to end	Day	47% 3 10% 27% 12% 1	4837
June	1st to 10th	Day	36% 4 14% 31% 14% 1	2660
	11th to 20th	Day	41% 5% 13% 23% 16% 1	2660
	21st to end	Day	40% 4 16% 27% 11% 2	2660
July	1st to 10th	Day	41% 6% 18% 24% 10% 1	4371
	11th to 20th	Day	24% 4 15% 35% 19% 2	4365
	21st to end	Day	32% 7% 14% 29% 16% 2	4588
August	1st to 10th	Day	40% 5% 11% 29% 13% 2	4090
	11th to 20th	Day	37% 5% 13% 33% 11%	4080
	21st to end	Day	34% 6% 15% 29% 15% 1	4280
September	1st to 10th	Day	36% 4 12% 32% 15%	2280
	11th to 20th	Day	37% 3 15% 33% 11% 1	2275
	21st to end	Day	41% 3 10% 32% 12% 1	1983
October	1st to 10th	Day	29% 2 7% 38% 23%	3160
	11th to 20th	Day	38% 2 12% 24% 21% 2	3140
	21st to end	Day	43% 3 13% 31% 10%	3380
November	1st to 10th	Day	43% 4 14% 22% 15% 3	1633
	11th to 20th	Day	55% 4 13% 17% 10% 1	1520
	21st to end	Day	49% 3 18% 22% 8% 1	1520
December	1st to 10th	Day	60% 3 15% 14% 8% 1	1520
	11th to 20th	Day	56% 3 18% 17% 6%	1915
	21st to end	Day	72% 2 8% 13% 5%	2783
January	1st to 10th	Night	63% 2 9% 19% 7%	4428
	11th to 20th	Night	60% 2 12% 18% 7%	4399
	21st to end	Night	63% 2 9% 20% 6% 1	4532
February	1st to 10th	Night	53% 2 11% 22% 10% 2	2470
	11th to 20th	Night	47% 3 12% 26% 10% 1	2404
	21st to end	Night	50% 2 11% 23% 12% 2	1955
March	1st to 10th	Night	39% 2 11% 31% 15% 1	3543
	11th to 20th	Night	40% 3 8% 30% 18% 1	3480
	21st to end	Night	59% 3 8% 21% 7% 2	3756
April	1st to 10th	Night	50% 3 9% 22% 15% 1	1900
	11th to 20th	Night	50% 3 9% 20% 16% 3	1875
	21st to end	Night	49% 2 9% 22% 16% 2	1742
May	1st to 10th	Night	44% 3 10% 20% 22% 1	2672
	11th to 20th	Night	34% 3 11% 29% 19% 5%	2507
	21st to end	Night	42% 3 10% 28% 16%	2751
June	1st to 10th	Night	33% 4 13% 31% 17% 2	1520
	11th to 20th	Night	37% 4 13% 25% 17% 3	1520
	21st to end	Night	29% 4 16% 30% 18% 3	1520
July	1st to 10th	Night	33% 5% 21% 28% 12% 2	2490
	11th to 20th	Night	22% 5% 16% 38% 17% 2	2482
	21st to end	Night	25% 5% 17% 31% 20% 2	2722
August	1st to 10th	Night	37% 4 12% 29% 15% 3	2826
	11th to 20th	Night	33% 4 14% 32% 15% 1	2825
	21st to end	Night	34% 4 17% 28% 16% 2	3378
September	1st to 10th	Night	29% 4 10% 36% 20% 1	1900
	11th to 20th	Night	32% 3 15% 33% 17% 1	1900
	21st to end	Night	33% 3 12% 32% 18% 1	2177
October	1st to 10th	Night	25% 2 6% 36% 28% 4	3800
	11th to 20th	Night	30% 3 13% 28% 23% 3	3779
	21st to end	Night	44% 3 10% 27% 16% 1	4168
November	1st to 10th	Night	41% 2 13% 26% 15% 2	2516
	11th to 20th	Night	51% 3 11% 20% 13% 1	2660
	21st to end	Night	48% 3 15% 23% 9% 1	2660
December	1st to 10th	Night	54% 3 14% 20% 7% 1	2660
	11th to 20th	Night	57% 3 13% 19% 7% 1	3281
	21st to end	Night	69% 2 9% 16% 5%	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	14% 13% 39% 22% 9% 2	270
	11th to 20th	Day	17% 12% 43% 22% 5% 1	270
	21st to end	Day	16% 9% 40% 24% 10% 2	297
February	1st to 10th	Day	15% 16% 45% 19% 3 1	270
	11th to 20th	Day	15% 19% 41% 19% 4 1	270
	21st to end	Day	23% 13% 37% 25% 2	225
March	1st to 10th	Day	16% 13% 44% 19% 6% 1	270
	11th to 20th	Day	24% 10% 36% 22% 8% 1	270
	21st to end	Day	32% 10% 29% 21% 6% 2	331
April	1st to 10th	Day	29% 12% 34% 19% 7%	460
	11th to 20th	Day	29% 17% 23% 21% 10% 1	452
	21st to end	Day	29% 10% 28% 23% 9% 2	616
May	1st to 10th	Day	22% 12% 32% 23% 9% 2	653
	11th to 20th	Day	20% 11% 27% 27% 11% 4	675
	21st to end	Day	20% 8% 27% 26% 16% 3	734
June	1st to 10th	Day	10% 8% 28% 31% 18% 5%	680
	11th to 20th	Day	15% 8% 33% 33% 10% 3	680
	21st to end	Day	14% 8% 30% 28% 15% 5%	680
July	1st to 10th	Day	10% 4 23% 31% 23% 9%	671
	11th to 20th	Day	8% 4 28% 32% 18% 9%	668
	21st to end	Day	7% 3 27% 37% 19% 7%	739
August	1st to 10th	Day	11% 3 21% 36% 22% 7%	676
	11th to 20th	Day	14% 3 18% 35% 23% 7%	665
	21st to end	Day	12% 4 27% 30% 22% 5%	601
September	1st to 10th	Day	17% 5% 27% 31% 14% 6%	490
	11th to 20th	Day	13% 3 29% 30% 20% 5%	485
	21st to end	Day	16% 12% 29% 26% 14% 3	300
October	1st to 10th	Day	18% 11% 26% 26% 15% 4	300
	11th to 20th	Day	19% 16% 39% 19% 7% 1	300
	21st to end	Day	25% 15% 35% 15% 8% 1	330
November	1st to 10th	Day	19% 14% 37% 20% 9% 1	279
	11th to 20th	Day	19% 19% 40% 18% 4	270
	21st to end	Day	20% 13% 44% 19% 4	270
December	1st to 10th	Day	16% 9% 41% 27% 5% 1	270
	11th to 20th	Day	20% 13% 39% 19% 8% 1	270
	21st to end	Day	27% 14% 38% 18% 3	297
January	1st to 10th	Night	15% 13% 38% 27% 7% 1	950
	11th to 20th	Night	18% 10% 41% 26% 5% 1	950
	21st to end	Night	18% 11% 37% 26% 7% 1	1045
February	1st to 10th	Night	13% 14% 41% 26% 6% 1	950
	11th to 20th	Night	14% 15% 43% 21% 6% 1	929
	21st to end	Night	18% 14% 34% 26% 6%	699
March	1st to 10th	Night	18% 13% 36% 26% 7% 1	648
	11th to 20th	Night	18% 10% 38% 27% 8% 1	570
	21st to end	Night	23% 9% 30% 26% 9% 3	627
April	1st to 10th	Night	20% 12% 38% 24% 5%	570
	11th to 20th	Night	25% 10% 31% 28% 6%	563
	21st to end	Night	24% 7% 32% 26% 9% 1	570
May	1st to 10th	Night	21% 7% 32% 32% 7% 1	570
	11th to 20th	Night	18% 5% 32% 32% 11% 2	561
	21st to end	Night	18% 5% 26% 37% 13% 1	617
June	1st to 10th	Night	10% 4 31% 39% 15% 1	570
	11th to 20th	Night	14% 3 33% 38% 12%	570
	21st to end	Night	11% 4 25% 44% 16% 1	570
July	1st to 10th	Night	8% 1 19% 41% 28% 3	555
	11th to 20th	Night	5% 4 25% 41% 24% 2	552
	21st to end	Night	7% 1 20% 49% 21% 2	624
August	1st to 10th	Night	8% 2 17% 45% 26% 2	567
	11th to 20th	Night	13% 1 18% 37% 27% 4	564
	21st to end	Night	10% 1 25% 38% 23% 3	627
September	1st to 10th	Night	11% 4 23% 41% 16% 5%	570
	11th to 20th	Night	14% 3 30% 32% 18% 2	570
	21st to end	Night	15% 8% 30% 32% 14% 1	657
October	1st to 10th	Night	17% 7% 29% 33% 13% 1	760
	11th to 20th	Night	18% 12% 35% 27% 8% 1	760
	21st to end	Night	22% 11% 31% 28% 7% 1	836
November	1st to 10th	Night	16% 13% 36% 27% 7% 1	819
	11th to 20th	Night	16% 15% 38% 24% 6%	950
	21st to end	Night	17% 16% 36% 23% 7%	950
December	1st to 10th	Night	17% 10% 39% 27% 6% 1	950
	11th to 20th	Night	19% 10% 40% 24% 7% 1	950
	21st to end	Night	25% 12% 34% 23% 5%	1045

Page generated at 2024-11-01 21:47:52. Version ac07

Copyright © 2024 Attilla Danko.