Juniper Hills Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Juniper Hills Park clear sky chart from 2005-11-06 to 2025-03-27.

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	7% 8% 3 6% 4 4 4 3 5% 6% 49%	113048
	Night	8% 9% 3 7% 5% 4 4 4 5% 6% 45%	115044
Transparency	Day	33% 7% 12% 21% 17% 9%	112791
	Night	37% 8% 14% 22% 14% 5%	114890
Seeing	Day	12% 12% 24% 27% 19% 7%	15003
	Night	12% 6% 20% 38% 21% 2	24204

By Month

Percentage Cloud Cover SW (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	15% 19% 6% 12% 7% 6% 6% 5% 5% 6% 14%	3639
	11th to 20th	Day	14% 11% 3 8% 5% 5% 4 3 5% 5% 37%	3640
	21st to end	Day	8% 10% 3 6% 5% 5% 5% 4 6% 8% 39%	4252
February	1st to 10th	Day	11% 15% 4 8% 5% 5% 6% 5% 6% 8% 28%	1800
	11th to 20th	Day	10% 14% 4 9% 5% 5% 5% 5% 5% 7% 32%	1761
	21st to end	Day	8% 15% 4 10% 6% 5% 6% 5% 6% 8% 28%	1650
March	1st to 10th	Day	6% 12% 5% 9% 6% 6% 6% 4 7% 9% 31%	3254
	11th to 20th	Day	6% 10% 3 7% 5% 4 4 3 5% 6% 46%	3600
	21st to end	Day	8% 11% 4 11% 7% 7% 6% 5% 6% 8% 26%	4076
April	1st to 10th	Day	11% 13% 3 8% 6% 5% 5% 5% 6% 7% 31%	2280
	11th to 20th	Day	9% 12% 4 8% 6% 5% 5% 3 5% 6% 37%	2249
	21st to end	Day	7% 10% 3 6% 5% 4 5% 3 6% 8% 42%	2360
May	1st to 10th	Day	12% 8% 3 6% 4 3 4 3 5% 6% 46%	4420
	11th to 20th	Day	5% 4 2 4 3 3 3 3 4 6% 64%	4377
	21st to end	Day	10% 7% 3 6% 4 4 4 4 6% 7% 45%	4813
June	1st to 10th	Day	11% 8% 3 6% 4 4 4 3 6% 7% 44%	2660
	11th to 20th	Day	8% 6% 3 6% 4 4 3 3 5% 7% 51%	2660
	21st to end	Day	4 3 1 3 3 2 3 3 4 6% 67%	2660
July	1st to 10th	Day	1 1 1 1 1 1 2 2 3 85%	4420
	11th to 20th	Day	1 1 1 2 2 1 2 2 2 4 82%	4420
	21st to end	Day	2 1 1 2 1 2 2 2 3 4 81%	4790
August	1st to 10th	Day	3 3 1 3 2 2 2 2 4 5% 73%	4251
	11th to 20th	Day	2 2 1 3 2 2 3 2 4 6% 72%	4001
	21st to end	Day	3 3 1 3 2 2 3 2 4 5% 72%	4180
September	1st to 10th	Day	2 2 1 2 2 2 2 3 4 5% 76%	2280
	11th to 20th	Day	5% 4 2 5% 4 4 4 3 5% 7% 58%	2280
	21st to end	Day	9% 4 2 5% 3 3 3 3 4 6% 58%	2038
October	1st to 10th	Day	6% 5% 2 4 3 3 3 3 4 6% 63%	3180
	11th to 20th	Day	6% 5% 2 6% 4 5% 5% 5% 7% 9% 46%	3161
	21st to end	Day	9% 9% 3 9% 5% 6% 5% 4 6% 7% 37%	3265
November	1st to 10th	Day	11% 13% 3 9% 5% 4 5% 4 6% 8% 31%	1764
	11th to 20th	Day	14% 10% 3 10% 7% 6% 6% 5% 7% 7% 24%	1615
	21st to end	Day	11% 11% 4 8% 6% 4 6% 4 7% 8% 33%	1600
December	1st to 10th	Day	9% 8% 3 5% 4 5% 4 4 6% 7% 45%	2620
	11th to 20th	Day	12% 15% 4 11% 7% 7% 7% 6% 8% 7% 18%	3028
	21st to end	Day	11% 16% 5% 12% 7% 7% 6% 5% 6% 7% 19%	4004
January	1st to 10th	Night	13% 17% 5% 14% 8% 7% 6% 5% 5% 5% 13%	6306
	11th to 20th	Night	12% 13% 3 9% 5% 4 4 3 5% 5% 36%	6320
	21st to end	Night	8% 12% 4 9% 6% 4 5% 3 5% 6% 39%	6714
February	1st to 10th	Night	9% 15% 3 9% 6% 6% 6% 5% 6% 7% 28%	2600
	11th to 20th	Night	10% 13% 4 9% 4 5% 5% 4 6% 7% 34%	2525
	21st to end	Night	10% 16% 4 8% 6% 5% 4 5% 6% 8% 29%	1980
March	1st to 10th	Night	7% 12% 4 8% 5% 6% 6% 5% 6% 8% 32%	3838
	11th to 20th	Night	5% 9% 3 6% 5% 4 4 3 5% 7% 50%	3600
	21st to end	Night	7% 12% 4 11% 7% 7% 7% 6% 8% 8% 24%	3714
April	1st to 10th	Night	11% 13% 4 7% 4 5% 5% 4 6% 6% 35%	1900
	11th to 20th	Night	9% 10% 3 8% 5% 5% 5% 4 5% 7% 40%	1879
	21st to end	Night	11% 10% 2 6% 5% 4 5% 4 6% 8% 40%	1818
May	1st to 10th	Night	13% 10% 3 5% 4 4 4 3 5% 6% 45%	2540
	11th to 20th	Night	6% 5% 2 4 3 3 2 2 4 5% 63%	2516
	21st to end	Night	11% 8% 3 6% 3 3 4 3 4 6% 50%	2762
June	1st to 10th	Night	13% 7% 2 7% 3 4 3 3 4 6% 46%	1520
	11th to 20th	Night	8% 6% 2 6% 3 3 3 3 4 7% 54%	1520
	21st to end	Night	5% 4 1 3 3 2 3 3 3 5% 69%	1520
July	1st to 10th	Night	1 1 1 1 1 1 1 2 3 86%	2540
	11th to 20th	Night	1 1 1 2 1 2 2 2 3 4 81%	2540
	21st to end	Night	1 1 1 1 1 1 2 2 3 3 84%	2761
August	1st to 10th	Night	1 2 1 3 2 2 3 3 5% 6% 72%	2679
	11th to 20th	Night	1 1 1 3 2 3 3 3 4 6% 74%	2836
	21st to end	Night	2 2 1 3 2 2 3 2 4 6% 74%	3498
September	1st to 10th	Night	2 1 1 2 1 2 2 2 4 4 79%	1900
	11th to 20th	Night	5% 3 2 4 3 3 4 3 5% 6% 62%	1900
	21st to end	Night	7% 4 2 4 2 3 4 2 4 6% 60%	2140
October	1st to 10th	Night	5% 5% 2 4 2 2 2 2 3 4 69%	3800
	11th to 20th	Night	7% 6% 2 6% 4 4 4 4 6% 8% 49%	3777
	21st to end	Night	9% 8% 3 8% 5% 6% 5% 4 6% 8% 37%	4296
November	1st to 10th	Night	14% 11% 3 9% 6% 5% 5% 3 5% 7% 32%	2535
	11th to 20th	Night	14% 11% 4 9% 6% 6% 5% 4 6% 7% 28%	2782
	21st to end	Night	9% 11% 3 7% 5% 5% 5% 4 6% 7% 36%	2800
December	1st to 10th	Night	7% 8% 2 6% 4 4 4 3 6% 7% 50%	4560
	11th to 20th	Night	12% 16% 5% 12% 8% 7% 7% 6% 6% 6% 17%	5176
	21st to end	Night	12% 13% 4 11% 7% 6% 6% 4 5% 6% 24%	6952

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	65% 12% 13% 10% 1	3639
	11th to 20th	Day	46% 10% 12% 22% 9% 1	3640
	21st to end	Day	41% 10% 13% 19% 13% 4	4252
February	1st to 10th	Day	52% 9% 15% 17% 6% 1	1800
	11th to 20th	Day	49% 10% 16% 17% 8% 1	1770
	21st to end	Day	49% 10% 18% 15% 7% 1	1650
March	1st to 10th	Day	42% 10% 13% 22% 11% 1	3254
	11th to 20th	Day	37% 7% 13% 31% 12%	3600
	21st to end	Day	49% 13% 16% 17% 5%	4076
April	1st to 10th	Day	49% 10% 15% 17% 9% 1	2280
	11th to 20th	Day	45% 8% 14% 18% 12% 3	2252
	21st to end	Day	36% 9% 15% 27% 11% 2	2360
May	1st to 10th	Day	35% 7% 15% 26% 17% 1	4420
	11th to 20th	Day	22% 5% 10% 29% 31% 3	4380
	21st to end	Day	34% 10% 20% 26% 10% 1	4814
June	1st to 10th	Day	38% 7% 13% 26% 13% 2	2660
	11th to 20th	Day	30% 6% 14% 31% 16% 3	2660
	21st to end	Day	18% 5% 12% 31% 26% 9%	2660
July	1st to 10th	Day	7% 2 5% 12% 24% 49%	4351
	11th to 20th	Day	8% 2 5% 9% 23% 54%	4345
	21st to end	Day	9% 2 5% 18% 36% 30%	4639
August	1st to 10th	Day	15% 2 5% 15% 40% 23%	4235
	11th to 20th	Day	14% 3 7% 32% 31% 12%	4040
	21st to end	Day	16% 3 7% 29% 30% 15%	4179
September	1st to 10th	Day	11% 4 7% 25% 33% 19%	2280
	11th to 20th	Day	24% 6% 12% 25% 23% 10%	2280
	21st to end	Day	27% 5% 14% 24% 22% 8%	2038
October	1st to 10th	Day	24% 5% 9% 26% 25% 12%	3180
	11th to 20th	Day	32% 7% 18% 25% 16% 2	3161
	21st to end	Day	44% 6% 10% 24% 13% 1	3265
November	1st to 10th	Day	49% 9% 14% 20% 8% 1	1764
	11th to 20th	Day	53% 12% 16% 14% 6%	1615
	21st to end	Day	46% 11% 17% 16% 9% 1	1600
December	1st to 10th	Day	38% 9% 13% 28% 11%	2620
	11th to 20th	Day	58% 10% 17% 13% 1	3028
	21st to end	Day	58% 11% 15% 14% 2	4004
January	1st to 10th	Night	65% 13% 13% 7% 2	6306
	11th to 20th	Night	45% 10% 12% 24% 8% 1	6320
	21st to end	Night	46% 10% 10% 18% 13% 4	6714
February	1st to 10th	Night	51% 11% 16% 14% 7%	2600
	11th to 20th	Night	46% 10% 17% 19% 7% 1	2527
	21st to end	Night	50% 11% 15% 16% 8% 1	1980
March	1st to 10th	Night	42% 11% 15% 23% 8% 1	3838
	11th to 20th	Night	31% 8% 18% 33% 10%	3600
	21st to end	Night	46% 18% 18% 14% 4	3714
April	1st to 10th	Night	45% 10% 20% 17% 8% 1	1900
	11th to 20th	Night	42% 9% 17% 19% 10% 2	1879
	21st to end	Night	41% 10% 15% 21% 10% 3	1818
May	1st to 10th	Night	34% 10% 16% 28% 12%	2540
	11th to 20th	Night	22% 5% 13% 39% 20% 1	2516
	21st to end	Night	30% 10% 32% 22% 6%	2762
June	1st to 10th	Night	37% 10% 14% 26% 12% 1	1520
	11th to 20th	Night	28% 7% 16% 34% 12% 3	1520
	21st to end	Night	19% 4 12% 33% 25% 7%	1520
July	1st to 10th	Night	7% 2 7% 14% 26% 44%	2500
	11th to 20th	Night	9% 2 5% 14% 19% 50%	2492
	21st to end	Night	7% 2 5% 21% 38% 28%	2674
August	1st to 10th	Night	13% 3 6% 17% 38% 23%	2671
	11th to 20th	Night	13% 3 9% 38% 28% 9%	2863
	21st to end	Night	12% 3 11% 31% 30% 12%	3498
September	1st to 10th	Night	10% 3 8% 29% 33% 17%	1900
	11th to 20th	Night	22% 6% 11% 26% 23% 12%	1900
	21st to end	Night	24% 5% 12% 26% 23% 10%	2140
October	1st to 10th	Night	22% 4 8% 28% 33% 5%	3800
	11th to 20th	Night	30% 6% 21% 24% 17% 2	3777
	21st to end	Night	42% 7% 11% 27% 12% 1	4296
November	1st to 10th	Night	49% 9% 13% 19% 10% 1	2535
	11th to 20th	Night	52% 11% 15% 18% 4	2782
	21st to end	Night	43% 10% 17% 20% 10% 1	2800
December	1st to 10th	Night	34% 7% 14% 34% 12%	4560
	11th to 20th	Night	63% 9% 15% 10% 3	5176
	21st to end	Night	54% 12% 18% 12% 4	6952

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% 16% 22% 23% 12% 2	200
	11th to 20th	Day	19% 8% 25% 32% 11% 6%	200
	21st to end	Day	17% 11% 23% 24% 20% 5%	325
February	1st to 10th	Day	20% 16% 22% 27% 13% 2	400
	11th to 20th	Day	18% 14% 28% 26% 13% 2	399
	21st to end	Day	20% 16% 26% 26% 11% 1	414
March	1st to 10th	Day	18% 16% 28% 26% 10% 1	500
	11th to 20th	Day	17% 17% 22% 27% 15% 3	500
	21st to end	Day	16% 20% 25% 26% 12% 1	531
April	1st to 10th	Day	23% 16% 23% 22% 12% 4	460
	11th to 20th	Day	17% 19% 28% 20% 10% 6%	452
	21st to end	Day	11% 21% 25% 23% 15% 5%	460
May	1st to 10th	Day	13% 17% 26% 24% 15% 5%	463
	11th to 20th	Day	16% 12% 25% 24% 15% 8%	488
	21st to end	Day	14% 10% 21% 28% 19% 8%	529
June	1st to 10th	Day	10% 14% 25% 23% 20% 9%	490
	11th to 20th	Day	9% 18% 27% 28% 14% 4	490
	21st to end	Day	4 9% 24% 31% 24% 8%	490
July	1st to 10th	Day	2 7% 24% 33% 25% 8%	486
	11th to 20th	Day	2 8% 25% 27% 27% 12%	484
	21st to end	Day	1 5% 24% 27% 27% 14%	531
August	1st to 10th	Day	2 5% 21% 34% 24% 14%	487
	11th to 20th	Day	1 5% 18% 28% 29% 18%	477
	21st to end	Day	4 7% 21% 28% 27% 12%	539
September	1st to 10th	Day	2 6% 23% 25% 29% 16%	490
	11th to 20th	Day	6% 7% 21% 28% 28% 9%	490
	21st to end	Day	12% 9% 18% 27% 27% 7%	490
October	1st to 10th	Day	9% 10% 21% 29% 22% 9%	490
	11th to 20th	Day	12% 11% 21% 23% 26% 7%	490
	21st to end	Day	14% 15% 24% 22% 20% 5%	431
November	1st to 10th	Day	17% 11% 24% 31% 15% 2	300
	11th to 20th	Day	16% 12% 25% 25% 16% 5%	207
	21st to end	Day	20% 9% 21% 30% 18% 3	200
December	1st to 10th	Day	14% 9% 24% 27% 17% 10%	200
	11th to 20th	Day	21% 10% 30% 31% 8% 2	200
	21st to end	Day	16% 13% 29% 28% 12% 3	220
January	1st to 10th	Night	18% 10% 28% 29% 13% 3	800
	11th to 20th	Night	16% 10% 23% 30% 20% 2	800
	21st to end	Night	15% 8% 18% 37% 20% 2	880
February	1st to 10th	Night	16% 9% 27% 33% 14% 2	800
	11th to 20th	Night	15% 8% 25% 34% 17% 1	784
	21st to end	Night	17% 11% 26% 35% 11%	660
March	1st to 10th	Night	16% 10% 26% 35% 13% 1	800
	11th to 20th	Night	12% 9% 24% 38% 16% 2	800
	21st to end	Night	10% 11% 29% 35% 15% 1	862
April	1st to 10th	Night	17% 8% 22% 34% 19% 1	760
	11th to 20th	Night	11% 9% 27% 34% 17% 2	751
	21st to end	Night	14% 8% 23% 36% 18% 1	678
May	1st to 10th	Night	11% 5% 24% 38% 20% 1	380
	11th to 20th	Night	12% 4 17% 41% 25% 1	374
	21st to end	Night	9% 5% 16% 44% 25% 1	411
June	1st to 10th	Night	13% 5% 16% 46% 19% 1	380
	11th to 20th	Night	8% 4 23% 44% 20% 1	380
	21st to end	Night	7% 1 14% 51% 27% 1	380
July	1st to 10th	Night	3 9% 60% 27% 1	370
	11th to 20th	Night	1 17% 58% 23% 1	368
	21st to end	Night	1 10% 52% 35% 2	416
August	1st to 10th	Night	1 1 6% 52% 36% 4	463
	11th to 20th	Night	2 1 6% 39% 46% 7%	575
	21st to end	Night	2 3 16% 45% 32% 2	836
September	1st to 10th	Night	2 2 16% 43% 34% 4	760
	11th to 20th	Night	5% 2 12% 41% 34% 6%	760
	21st to end	Night	9% 3 13% 38% 32% 5%	760
October	1st to 10th	Night	11% 3 17% 40% 26% 3	760
	11th to 20th	Night	12% 4 17% 36% 27% 4	760
	21st to end	Night	13% 7% 20% 38% 18% 5%	836
November	1st to 10th	Night	16% 8% 23% 36% 17% 1	780
	11th to 20th	Night	19% 9% 24% 31% 16% 1	800
	21st to end	Night	14% 8% 22% 35% 19% 3	800
December	1st to 10th	Night	16% 6% 21% 34% 20% 3	800
	11th to 20th	Night	19% 7% 24% 34% 15% 1	800
	21st to end	Night	20% 11% 28% 29% 11% 1	880

Page generated at 2025-03-24 06:04:26. Version ac07

Copyright © 2025 Attilla Danko.