Cherry Springs State Park
Clear Sky Chart
History

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

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	17% 11% 4 9% 5% 5% 5% 4 5% 7% 30%	101440
	Night	17% 12% 4 9% 5% 4 4 3 5% 6% 30%	97612
Transparency	Day	52% 6% 11% 20% 10% 1	105044
	Night	52% 6% 11% 20% 10% 1	102097
Seeing	Day	26% 18% 28% 17% 8% 3	14704
	Night	24% 17% 27% 22% 9% 1	24077

By Month

Percentage Cloud Cover NE (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% 23% 9% 14% 4 3 3 2 3 3 22%	2517
	11th to 20th	Day	11% 19% 9% 19% 7% 4 3 2 4 4 18%	2750
	21st to end	Day	23% 16% 9% 14% 6% 4 4 2 3 4 16%	3124
February	1st to 10th	Day	15% 18% 6% 13% 7% 5% 5% 3 4 4 20%	1710
	11th to 20th	Day	13% 14% 6% 14% 7% 5% 5% 3 4 6% 24%	1663
	21st to end	Day	19% 14% 2 12% 6% 3 3 2 4 6% 27%	1539
March	1st to 10th	Day	20% 14% 6% 9% 4 3 3 3 4 7% 28%	3388
	11th to 20th	Day	11% 16% 7% 10% 6% 4 4 2 4 5% 31%	3480
	21st to end	Day	15% 12% 4 9% 6% 5% 4 4 5% 5% 30%	3862
April	1st to 10th	Day	17% 16% 4 7% 5% 4 4 3 5% 6% 29%	2280
	11th to 20th	Day	18% 12% 4 7% 5% 4 5% 4 5% 5% 32%	2254
	21st to end	Day	21% 10% 3 6% 5% 4 4 3 5% 5% 33%	2376
May	1st to 10th	Day	28% 9% 3 6% 4 4 4 3 5% 6% 29%	4126
	11th to 20th	Day	23% 11% 3 8% 6% 4 5% 4 5% 6% 25%	4398
	21st to end	Day	15% 7% 2 6% 5% 5% 5% 4 6% 8% 39%	4837
June	1st to 10th	Day	16% 8% 3 7% 5% 5% 5% 4 6% 8% 33%	2660
	11th to 20th	Day	16% 7% 3 7% 5% 6% 6% 5% 6% 9% 32%	2660
	21st to end	Day	15% 7% 2 6% 5% 5% 5% 5% 6% 9% 35%	2660
July	1st to 10th	Day	10% 7% 2 7% 6% 5% 6% 5% 7% 10% 35%	4440
	11th to 20th	Day	10% 7% 3 8% 5% 6% 6% 5% 7% 9% 35%	4440
	21st to end	Day	11% 7% 3 7% 6% 6% 6% 4 7% 8% 35%	4512
August	1st to 10th	Day	22% 7% 3 7% 4 5% 5% 4 6% 8% 29%	4104
	11th to 20th	Day	16% 7% 3 8% 5% 6% 6% 5% 8% 8% 27%	4023
	21st to end	Day	16% 6% 2 6% 4 4 5% 5% 7% 8% 37%	4180
September	1st to 10th	Day	19% 7% 3 6% 3 4 4 4 5% 6% 39%	2280
	11th to 20th	Day	14% 6% 3 7% 4 4 4 3 5% 6% 43%	2274
	21st to end	Day	25% 6% 2 7% 4 5% 4 3 5% 6% 32%	1986
October	1st to 10th	Day	18% 8% 3 8% 4 4 5% 4 5% 8% 33%	1900
	11th to 20th	Day	21% 10% 4 7% 5% 4 4 4 5% 5% 32%	1900
	21st to end	Day	22% 13% 3 8% 5% 4 4 4 5% 6% 27%	2090
November	1st to 10th	Day	12% 12% 4 8% 4 5% 4 3 5% 7% 37%	1765
	11th to 20th	Day	18% 15% 5% 10% 4 4 4 4 5% 6% 26%	1544
	21st to end	Day	18% 18% 5% 9% 6% 4 4 3 4 6% 23%	1520
December	1st to 10th	Day	19% 20% 5% 13% 6% 5% 4 3 4 5% 16%	1520
	11th to 20th	Day	19% 16% 6% 12% 4 4 4 3 5% 6% 19%	1906
	21st to end	Day	22% 24% 7% 10% 4 4 4 3 4 4 15%	2772
January	1st to 10th	Night	15% 17% 9% 11% 5% 5% 5% 3 5% 6% 18%	4429
	11th to 20th	Night	14% 17% 7% 17% 7% 5% 4 3 5% 5% 15%	4207
	21st to end	Night	22% 17% 6% 14% 8% 5% 4 2 3 4 16%	4532
February	1st to 10th	Night	13% 15% 6% 11% 8% 6% 4 4 4 5% 24%	2470
	11th to 20th	Night	14% 13% 5% 12% 7% 4 5% 4 5% 7% 23%	2403
	21st to end	Night	17% 12% 5% 12% 6% 5% 4 4 5% 5% 24%	1913
March	1st to 10th	Night	19% 16% 4 9% 5% 4 4 3 4 5% 27%	3448
	11th to 20th	Night	14% 16% 8% 10% 5% 4 4 4 4 6% 26%	3479
	21st to end	Night	14% 12% 3 8% 5% 4 4 3 4 6% 38%	3769
April	1st to 10th	Night	19% 13% 4 8% 5% 5% 4 4 4 6% 28%	1900
	11th to 20th	Night	18% 12% 2 8% 5% 4 3 3 4 6% 35%	1875
	21st to end	Night	17% 12% 3 7% 4 5% 4 3 5% 6% 35%	1819
May	1st to 10th	Night	28% 11% 3 6% 4 3 3 3 4 5% 31%	2815
	11th to 20th	Night	24% 12% 3 6% 4 4 5% 3 5% 7% 28%	2495
	21st to end	Night	13% 8% 3 7% 5% 5% 4 4 6% 7% 38%	2738
June	1st to 10th	Night	13% 7% 2 7% 6% 5% 4 3 6% 8% 38%	1520
	11th to 20th	Night	12% 7% 3 5% 4 5% 5% 5% 7% 8% 39%	1520
	21st to end	Night	13% 6% 2 7% 4 4 5% 4 6% 7% 41%	1520
July	1st to 10th	Night	12% 7% 3 7% 5% 5% 4 4 6% 7% 39%	2520
	11th to 20th	Night	10% 6% 2 6% 4 4 5% 3 6% 10% 42%	2520
	21st to end	Night	14% 6% 3 7% 4 4 3 3 5% 7% 43%	3023
August	1st to 10th	Night	19% 7% 2 7% 4 4 5% 4 5% 7% 36%	2825
	11th to 20th	Night	19% 8% 3 6% 4 3 4 3 5% 7% 39%	2785
	21st to end	Night	14% 6% 2 5% 4 4 5% 3 6% 8% 44%	3463
September	1st to 10th	Night	16% 7% 2 7% 4 3 3 3 5% 6% 44%	1900
	11th to 20th	Night	13% 6% 2 6% 3 4 3 3 5% 6% 48%	1904
	21st to end	Night	21% 8% 3 6% 4 5% 4 3 5% 6% 36%	2194
October	1st to 10th	Night	19% 9% 2 6% 4 4 4 3 5% 6% 39%	2280
	11th to 20th	Night	20% 11% 3 6% 4 4 4 3 5% 6% 35%	2280
	21st to end	Night	22% 14% 3 7% 4 3 4 3 5% 6% 29%	2508
November	1st to 10th	Night	12% 9% 3 7% 5% 5% 4 4 5% 6% 39%	2435
	11th to 20th	Night	17% 13% 4 9% 6% 4 4 3 5% 6% 27%	2631
	21st to end	Night	16% 15% 6% 10% 6% 5% 4 4 6% 7% 23%	2660
December	1st to 10th	Night	19% 17% 6% 10% 6% 5% 5% 4 5% 5% 17%	2660
	11th to 20th	Night	17% 16% 5% 13% 7% 5% 4 3 4 4 21%	3288
	21st to end	Night	21% 17% 8% 11% 6% 4 4 4 5% 5% 14%	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	66% 4 9% 15% 4 2	2518
	11th to 20th	Day	70% 4 8% 12% 5% 1	2750
	21st to end	Day	73% 3 7% 12% 4 1	3124
February	1st to 10th	Day	65% 4 11% 13% 6%	1710
	11th to 20th	Day	60% 5% 7% 19% 8% 1	1672
	21st to end	Day	59% 4 8% 20% 8% 2	1539
March	1st to 10th	Day	56% 5% 9% 23% 6% 1	3391
	11th to 20th	Day	53% 5% 13% 18% 8% 2	3480
	21st to end	Day	51% 8% 7% 20% 12% 2	3862
April	1st to 10th	Day	55% 5% 9% 18% 11% 2	2280
	11th to 20th	Day	52% 6% 10% 17% 14% 1	2254
	21st to end	Day	51% 6% 8% 19% 14% 2	2376
May	1st to 10th	Day	54% 6% 8% 22% 9% 1	4138
	11th to 20th	Day	57% 8% 11% 17% 7% 1	4402
	21st to end	Day	40% 8% 14% 23% 13% 1	4837
June	1st to 10th	Day	47% 8% 11% 20% 13% 1	2660
	11th to 20th	Day	47% 7% 14% 19% 12% 1	2660
	21st to end	Day	44% 7% 13% 24% 12%	2660
July	1st to 10th	Day	43% 6% 15% 25% 11% 1	4370
	11th to 20th	Day	44% 5% 13% 25% 13%	4365
	21st to end	Day	44% 5% 13% 25% 12% 1	4368
August	1st to 10th	Day	52% 6% 13% 20% 9%	4091
	11th to 20th	Day	50% 6% 14% 23% 6%	4062
	21st to end	Day	43% 4 11% 30% 10% 1	4180
September	1st to 10th	Day	45% 5% 10% 24% 15% 2	2280
	11th to 20th	Day	40% 6% 11% 24% 18% 1	2274
	21st to end	Day	51% 5% 11% 18% 13% 1	1986
October	1st to 10th	Day	45% 4 9% 22% 18% 1	3160
	11th to 20th	Day	46% 3 10% 20% 17% 3	3140
	21st to end	Day	40% 4 16% 27% 11% 1	3428
November	1st to 10th	Day	45% 6% 12% 21% 14% 3	1765
	11th to 20th	Day	57% 5% 11% 19% 6% 2	1544
	21st to end	Day	61% 6% 10% 17% 6% 1	1520
December	1st to 10th	Day	69% 5% 10% 10% 5%	1520
	11th to 20th	Day	64% 5% 12% 14% 5%	1906
	21st to end	Day	72% 6% 10% 11% 2	2772
January	1st to 10th	Night	63% 7% 10% 15% 5%	4429
	11th to 20th	Night	67% 6% 11% 11% 4 1	4207
	21st to end	Night	71% 5% 7% 12% 4 1	4532
February	1st to 10th	Night	59% 6% 12% 15% 7%	2470
	11th to 20th	Night	57% 6% 10% 19% 7% 1	2405
	21st to end	Night	58% 5% 11% 15% 9% 2	1913
March	1st to 10th	Night	59% 6% 9% 18% 7% 1	3458
	11th to 20th	Night	55% 8% 13% 17% 7% 1	3480
	21st to end	Night	46% 5% 8% 21% 17% 2	3769
April	1st to 10th	Night	56% 5% 8% 18% 12% 1	1900
	11th to 20th	Night	49% 6% 11% 20% 12% 2	1875
	21st to end	Night	48% 5% 10% 21% 14% 2	1819
May	1st to 10th	Night	56% 5% 9% 22% 8% 1	2822
	11th to 20th	Night	54% 8% 13% 16% 8% 1	2496
	21st to end	Night	40% 10% 13% 18% 14% 4	2739
June	1st to 10th	Night	40% 8% 14% 23% 14% 1	1520
	11th to 20th	Night	39% 8% 15% 25% 12% 2	1520
	21st to end	Night	40% 7% 13% 27% 13%	1520
July	1st to 10th	Night	44% 5% 13% 21% 16% 1	2480
	11th to 20th	Night	36% 5% 17% 26% 15% 1	2472
	21st to end	Night	41% 5% 12% 23% 19% 1	2927
August	1st to 10th	Night	47% 7% 13% 25% 7% 1	2814
	11th to 20th	Night	44% 5% 14% 28% 9%	2812
	21st to end	Night	38% 5% 12% 33% 11% 1	3463
September	1st to 10th	Night	41% 5% 11% 25% 15% 2	1900
	11th to 20th	Night	35% 5% 13% 26% 19% 2	1904
	21st to end	Night	47% 6% 13% 21% 12% 1	2194
October	1st to 10th	Night	48% 4 8% 22% 18% 1	3800
	11th to 20th	Night	41% 4 12% 22% 15% 6%	3779
	21st to end	Night	42% 3 16% 25% 13% 2	4120
November	1st to 10th	Night	41% 6% 14% 22% 14% 2	2435
	11th to 20th	Night	55% 6% 12% 16% 9% 2	2631
	21st to end	Night	57% 6% 13% 19% 5% 1	2660
December	1st to 10th	Night	64% 8% 11% 12% 4	2660
	11th to 20th	Night	64% 5% 10% 18% 4	3288
	21st to end	Night	68% 7% 11% 12% 2	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	36% 25% 27% 9% 4	180
	11th to 20th	Day	39% 29% 24% 6% 1	247
	21st to end	Day	33% 27% 31% 8% 1	297
February	1st to 10th	Day	39% 29% 28% 4	270
	11th to 20th	Day	40% 27% 30% 3	270
	21st to end	Day	42% 23% 27% 7% 1	351
March	1st to 10th	Day	32% 25% 28% 12% 3	460
	11th to 20th	Day	31% 26% 27% 12% 3 1	460
	21st to end	Day	35% 23% 25% 12% 3 1	506
April	1st to 10th	Day	32% 25% 26% 12% 4 2	460
	11th to 20th	Day	31% 24% 25% 12% 6% 3	452
	21st to end	Day	31% 20% 32% 12% 5% 1	460
May	1st to 10th	Day	33% 18% 27% 12% 7% 3	463
	11th to 20th	Day	27% 17% 30% 15% 7% 3	487
	21st to end	Day	21% 13% 28% 22% 11% 5%	529
June	1st to 10th	Day	18% 17% 31% 23% 9% 2	490
	11th to 20th	Day	19% 15% 26% 24% 14% 1	490
	21st to end	Day	20% 13% 34% 23% 8% 2	490
July	1st to 10th	Day	14% 10% 29% 25% 14% 7%	485
	11th to 20th	Day	12% 8% 32% 29% 14% 5%	484
	21st to end	Day	14% 11% 32% 25% 13% 4	532
August	1st to 10th	Day	15% 9% 26% 28% 16% 7%	486
	11th to 20th	Day	17% 8% 28% 26% 15% 7%	479
	21st to end	Day	14% 12% 28% 24% 13% 8%	539
September	1st to 10th	Day	22% 11% 20% 24% 14% 8%	490
	11th to 20th	Day	14% 9% 25% 23% 21% 8%	490
	21st to end	Day	27% 14% 23% 19% 13% 4	490
October	1st to 10th	Day	25% 13% 25% 20% 13% 4	490
	11th to 20th	Day	25% 20% 31% 16% 7% 2	490
	21st to end	Day	32% 21% 28% 15% 5%	539
November	1st to 10th	Day	25% 20% 29% 16% 10% 1	406
	11th to 20th	Day	35% 24% 26% 12% 2	204
	21st to end	Day	33% 27% 31% 8% 1 1	180
December	1st to 10th	Day	40% 26% 25% 5% 3 1	180
	11th to 20th	Day	38% 26% 26% 9% 1	180
	21st to end	Day	40% 26% 29% 4 1	198
January	1st to 10th	Night	28% 27% 31% 11% 3	760
	11th to 20th	Night	29% 25% 29% 15% 2	760
	21st to end	Night	26% 28% 30% 15% 1	836
February	1st to 10th	Night	27% 24% 34% 13% 1	760
	11th to 20th	Night	30% 28% 31% 10% 1	743
	21st to end	Night	33% 25% 28% 13% 2	628
March	1st to 10th	Night	25% 26% 32% 15% 2	760
	11th to 20th	Night	31% 24% 24% 17% 3	760
	21st to end	Night	24% 24% 32% 16% 4 1	836
April	1st to 10th	Night	27% 22% 29% 19% 3	760
	11th to 20th	Night	27% 17% 31% 19% 6% 1	751
	21st to end	Night	24% 15% 30% 25% 5%	679
May	1st to 10th	Night	26% 13% 24% 27% 10%	565
	11th to 20th	Night	20% 12% 28% 31% 9%	374
	21st to end	Night	16% 9% 24% 33% 17% 1	411
June	1st to 10th	Night	16% 7% 29% 33% 13% 1	380
	11th to 20th	Night	15% 9% 22% 43% 11%	380
	21st to end	Night	13% 7% 31% 36% 12% 1	380
July	1st to 10th	Night	12% 6% 22% 38% 20% 2	370
	11th to 20th	Night	10% 3 22% 42% 23% 1	368
	21st to end	Night	13% 5% 19% 42% 18% 2	586
August	1st to 10th	Night	13% 4 20% 38% 24% 1	567
	11th to 20th	Night	17% 5% 17% 33% 25% 3	564
	21st to end	Night	14% 6% 20% 35% 23% 3	823
September	1st to 10th	Night	19% 8% 22% 30% 18% 3	760
	11th to 20th	Night	15% 8% 20% 28% 26% 4	760
	21st to end	Night	24% 11% 22% 24% 16% 3	760
October	1st to 10th	Night	23% 12% 24% 21% 17% 2	760
	11th to 20th	Night	25% 17% 26% 23% 7% 1	760
	21st to end	Night	30% 17% 28% 21% 4	836
November	1st to 10th	Night	18% 19% 33% 24% 7%	764
	11th to 20th	Night	28% 20% 28% 18% 5% 1	760
	21st to end	Night	26% 20% 33% 17% 3 1	760
December	1st to 10th	Night	32% 24% 28% 12% 4	760
	11th to 20th	Night	29% 24% 29% 15% 3	760
	21st to end	Night	31% 24% 30% 14% 1	836

Page generated at 2024-11-03 13:19:02. Version ac07

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