Oak Mountain State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Oak Mountain State Park clear sky chart from 2005-11-06 to 2024-06-30.

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% 7% 2 6% 4 5% 5% 4 6% 8% 41%	89647
	Night	13% 7% 2 6% 4 4 4 4 5% 7% 44%	89454
Transparency	Day	40% 7% 11% 19% 18% 5%	89424
	Night	38% 6% 10% 19% 20% 6%	89281
Seeing	Day	15% 10% 22% 24% 19% 9%	14048
	Night	14% 8% 23% 29% 22% 4	24063

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	16% 13% 4 7% 4 3 4 4 5% 5% 37%	2836
	11th to 20th	Day	15% 7% 3 5% 4 3 3 2 4 5% 50%	2977
	21st to end	Day	24% 9% 2 4 3 2 2 3 3 6% 41%	3476
February	1st to 10th	Day	18% 10% 3 7% 4 4 3 3 4 6% 38%	1900
	11th to 20th	Day	23% 8% 2 5% 4 3 3 3 4 5% 40%	1848
	21st to end	Day	20% 8% 3 6% 5% 4 3 3 4 5% 37%	1570
March	1st to 10th	Day	22% 9% 3 7% 4 3 4 3 5% 6% 35%	3120
	11th to 20th	Day	14% 8% 3 6% 4 4 4 4 6% 7% 41%	3342
	21st to end	Day	16% 7% 3 6% 5% 4 5% 4 6% 7% 38%	4000
April	1st to 10th	Day	12% 6% 2 6% 5% 4 4 3 6% 8% 45%	2280
	11th to 20th	Day	12% 6% 3 6% 4 4 4 3 6% 7% 45%	2254
	21st to end	Day	8% 5% 1 5% 4 4 5% 3 6% 8% 50%	2280
May	1st to 10th	Day	9% 5% 2 6% 4 5% 5% 5% 7% 10% 43%	4011
	11th to 20th	Day	16% 7% 2 6% 4 4 5% 4 6% 8% 38%	4081
	21st to end	Day	9% 5% 2 7% 5% 4 5% 4 6% 9% 43%	4476
June	1st to 10th	Day	9% 7% 3 7% 6% 7% 5% 6% 8% 10% 33%	2470
	11th to 20th	Day	6% 4 1 5% 5% 6% 6% 6% 8% 11% 42%	2470
	21st to end	Day	6% 4 2 6% 6% 5% 6% 5% 8% 11% 40%	2457
July	1st to 10th	Day	9% 6% 2 6% 6% 7% 7% 6% 9% 10% 32%	2340
	11th to 20th	Day	8% 5% 2 7% 6% 7% 8% 7% 10% 12% 28%	2340
	21st to end	Day	6% 4 3 7% 7% 7% 9% 7% 9% 11% 31%	2481
August	1st to 10th	Day	6% 4 2 6% 5% 8% 7% 8% 10% 12% 31%	2148
	11th to 20th	Day	11% 6% 2 8% 6% 7% 6% 6% 8% 9% 32%	2125
	21st to end	Day	11% 7% 2 8% 5% 6% 6% 6% 9% 8% 31%	2376
September	1st to 10th	Day	9% 6% 3 8% 5% 5% 6% 4 6% 8% 41%	2114
	11th to 20th	Day	13% 7% 2 6% 4 4 5% 4 5% 7% 42%	1980
	21st to end	Day	9% 6% 2 6% 4 5% 4 4 4 7% 51%	1980
October	1st to 10th	Day	9% 4 2 5% 4 4 5% 3 5% 6% 53%	1980
	11th to 20th	Day	9% 5% 2 5% 3 4 3 2 5% 7% 55%	1980
	21st to end	Day	12% 5% 2 5% 3 3 4 2 4 6% 53%	1876
November	1st to 10th	Day	12% 6% 2 4 4 3 3 3 3 5% 54%	1672
	11th to 20th	Day	13% 7% 2 5% 3 3 3 3 4 6% 52%	1710
	21st to end	Day	14% 7% 2 6% 3 4 4 4 4 7% 45%	1710
December	1st to 10th	Day	20% 8% 3 6% 4 4 4 3 5% 6% 38%	1710
	11th to 20th	Day	17% 8% 3 6% 5% 3 4 3 3 4 42%	2153
	21st to end	Day	18% 10% 4 7% 4 4 3 3 5% 7% 36%	3124
January	1st to 10th	Night	17% 12% 3 5% 3 3 4 3 4 5% 40%	4109
	11th to 20th	Night	14% 9% 3 6% 4 4 3 3 4 5% 45%	3978
	21st to end	Night	22% 13% 2 5% 3 3 3 2 3 3 40%	4180
February	1st to 10th	Night	17% 8% 2 7% 4 3 4 3 5% 5% 42%	2280
	11th to 20th	Night	19% 9% 3 6% 3 3 3 3 4 5% 43%	2218
	21st to end	Night	19% 7% 2 6% 4 4 4 3 6% 7% 39%	1884
March	1st to 10th	Night	23% 11% 3 6% 3 3 3 2 4 5% 35%	3733
	11th to 20th	Night	11% 6% 2 5% 3 3 4 4 6% 7% 48%	3618
	21st to end	Night	15% 7% 2 8% 5% 5% 4 3 4 6% 40%	3658
April	1st to 10th	Night	11% 5% 2 6% 4 4 4 4 6% 8% 47%	1900
	11th to 20th	Night	13% 5% 2 6% 4 3 3 3 5% 7% 49%	1875
	21st to end	Night	9% 5% 2 5% 4 4 4 3 5% 7% 53%	1900
May	1st to 10th	Night	8% 5% 3 7% 5% 5% 5% 4 7% 8% 43%	2881
	11th to 20th	Night	16% 7% 3 6% 4 4 5% 4 6% 7% 39%	2812
	21st to end	Night	5% 3 1 4 4 4 6% 5% 8% 12% 48%	3079
June	1st to 10th	Night	6% 6% 2 6% 5% 5% 8% 6% 8% 11% 37%	1710
	11th to 20th	Night	4 4 1 3 3 5% 6% 5% 9% 11% 50%	1710
	21st to end	Night	5% 5% 1 6% 6% 4 5% 5% 8% 11% 43%	1701
July	1st to 10th	Night	6% 6% 2 6% 5% 5% 7% 6% 9% 10% 37%	1620
	11th to 20th	Night	5% 5% 2 6% 5% 6% 5% 6% 9% 11% 39%	1620
	21st to end	Night	4 4 2 6% 6% 5% 6% 6% 8% 10% 41%	1832
August	1st to 10th	Night	4 3 1 5% 5% 5% 6% 6% 9% 14% 40%	1790
	11th to 20th	Night	7% 5% 2 7% 6% 5% 6% 5% 6% 13% 39%	1776
	21st to end	Night	9% 6% 2 8% 5% 5% 6% 5% 7% 8% 39%	1980
September	1st to 10th	Night	8% 5% 2 8% 6% 4 5% 4 7% 9% 43%	1826
	11th to 20th	Night	11% 6% 2 6% 4 4 4 4 6% 8% 47%	1980
	21st to end	Night	6% 5% 2 5% 4 4 4 4 6% 6% 54%	1980
October	1st to 10th	Night	8% 4 2 5% 3 3 3 3 4 5% 60%	1980
	11th to 20th	Night	10% 5% 2 5% 3 3 4 3 4 6% 55%	1980
	21st to end	Night	14% 6% 2 4 3 2 4 2 3 4 54%	2474
November	1st to 10th	Night	11% 5% 1 4 3 2 3 3 5% 5% 57%	2406
	11th to 20th	Night	12% 6% 3 5% 3 3 3 3 4 6% 54%	2470
	21st to end	Night	12% 6% 2 5% 4 4 4 3 6% 6% 47%	2470
December	1st to 10th	Night	18% 7% 2 6% 4 3 4 4 4 6% 42%	2470
	11th to 20th	Night	17% 7% 2 6% 3 3 3 3 4 4 47%	3042
	21st to end	Night	18% 8% 3 7% 4 4 4 4 6% 7% 35%	4532

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% 4 5% 15% 23% 5%	2837
	11th to 20th	Day	38% 4 7% 25% 22% 4	2977
	21st to end	Day	46% 3 7% 17% 20% 8%	3476
February	1st to 10th	Day	48% 3 7% 19% 18% 5%	1900
	11th to 20th	Day	48% 4 5% 17% 20% 7%	1858
	21st to end	Day	49% 5% 6% 12% 21% 8%	1570
March	1st to 10th	Day	51% 4 9% 11% 18% 7%	3120
	11th to 20th	Day	42% 5% 8% 17% 20% 8%	3342
	21st to end	Day	44% 5% 10% 16% 20% 5%	4000
April	1st to 10th	Day	37% 5% 10% 20% 20% 8%	2280
	11th to 20th	Day	39% 5% 7% 18% 23% 8%	2254
	21st to end	Day	31% 6% 10% 24% 25% 3	2280
May	1st to 10th	Day	33% 8% 13% 26% 17% 2	4048
	11th to 20th	Day	41% 6% 13% 27% 11% 2	4085
	21st to end	Day	34% 8% 13% 27% 16% 2	4489
June	1st to 10th	Day	41% 9% 15% 20% 14% 1	2470
	11th to 20th	Day	31% 10% 17% 24% 16% 2	2470
	21st to end	Day	34% 10% 18% 23% 11% 4	2457
July	1st to 10th	Day	39% 14% 19% 18% 9% 1	2275
	11th to 20th	Day	41% 14% 20% 15% 9% 1	2271
	21st to end	Day	39% 14% 20% 19% 9%	2342
August	1st to 10th	Day	36% 14% 20% 23% 6% 1	2136
	11th to 20th	Day	43% 11% 17% 16% 10% 3	2125
	21st to end	Day	44% 10% 16% 17% 10% 3	2376
September	1st to 10th	Day	40% 8% 13% 17% 17% 5%	2114
	11th to 20th	Day	40% 8% 11% 18% 19% 4	1980
	21st to end	Day	33% 6% 9% 21% 23% 8%	1980
October	1st to 10th	Day	32% 5% 10% 19% 25% 10%	1980
	11th to 20th	Day	30% 4 8% 22% 28% 8%	1980
	21st to end	Day	34% 4 5% 16% 31% 10%	1876
November	1st to 10th	Day	34% 4 6% 17% 29% 11%	1672
	11th to 20th	Day	35% 3 6% 19% 26% 11%	1710
	21st to end	Day	39% 5% 8% 17% 23% 8%	1710
December	1st to 10th	Day	46% 6% 9% 15% 19% 6%	1710
	11th to 20th	Day	47% 3 6% 16% 22% 5%	2150
	21st to end	Day	48% 3 8% 18% 20% 2	3124
January	1st to 10th	Night	46% 3 6% 15% 25% 4	4109
	11th to 20th	Night	42% 3 5% 22% 19% 8%	3978
	21st to end	Night	51% 3 4 15% 23% 5%	4180
February	1st to 10th	Night	44% 3 6% 18% 20% 8%	2280
	11th to 20th	Night	45% 4 5% 17% 18% 10%	2219
	21st to end	Night	44% 5% 8% 14% 19% 9%	1884
March	1st to 10th	Night	52% 4 8% 14% 16% 7%	3733
	11th to 20th	Night	34% 5% 10% 18% 22% 11%	3618
	21st to end	Night	45% 4 7% 20% 19% 5%	3658
April	1st to 10th	Night	35% 6% 10% 21% 20% 8%	1900
	11th to 20th	Night	34% 5% 8% 19% 23% 11%	1875
	21st to end	Night	31% 5% 11% 24% 23% 6%	1900
May	1st to 10th	Night	35% 10% 12% 20% 20% 3	2909
	11th to 20th	Night	41% 8% 14% 23% 12% 2	2813
	21st to end	Night	24% 11% 14% 30% 18% 3	3087
June	1st to 10th	Night	36% 12% 14% 19% 17% 1	1710
	11th to 20th	Night	24% 8% 22% 27% 16% 3	1710
	21st to end	Night	30% 11% 17% 21% 17% 5%	1701
July	1st to 10th	Night	36% 12% 19% 21% 9% 3	1575
	11th to 20th	Night	32% 13% 23% 20% 9% 2	1566
	21st to end	Night	32% 13% 23% 21% 10% 1	1730
August	1st to 10th	Night	28% 13% 21% 29% 9% 1	1778
	11th to 20th	Night	35% 12% 21% 16% 11% 4	1776
	21st to end	Night	40% 10% 15% 19% 12% 4	1980
September	1st to 10th	Night	36% 8% 16% 18% 17% 5%	1826
	11th to 20th	Night	34% 9% 11% 20% 20% 5%	1980
	21st to end	Night	28% 6% 11% 22% 24% 8%	1980
October	1st to 10th	Night	26% 5% 9% 21% 25% 13%	1980
	11th to 20th	Night	30% 4 8% 21% 25% 12%	1980
	21st to end	Night	34% 3 6% 15% 29% 13%	2474
November	1st to 10th	Night	29% 4 8% 17% 27% 14%	2406
	11th to 20th	Night	32% 4 6% 18% 26% 14%	2470
	21st to end	Night	37% 5% 7% 18% 24% 9%	2470
December	1st to 10th	Night	42% 5% 9% 18% 21% 5%	2470
	11th to 20th	Night	41% 4 7% 14% 29% 6%	3044
	21st to end	Night	47% 4 9% 18% 20% 3	4532

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	27% 20% 31% 16% 4	270
	11th to 20th	Day	26% 20% 31% 16% 7%	270
	21st to end	Day	24% 26% 37% 10% 2 1	297
February	1st to 10th	Day	28% 20% 37% 13% 3	270
	11th to 20th	Day	39% 16% 30% 13% 1	270
	21st to end	Day	27% 23% 42% 8%	225
March	1st to 10th	Day	27% 22% 31% 15% 5%	270
	11th to 20th	Day	22% 17% 37% 17% 7% 1	374
	21st to end	Day	23% 18% 31% 20% 8%	506
April	1st to 10th	Day	21% 14% 31% 22% 10% 1	460
	11th to 20th	Day	17% 14% 31% 23% 12% 2	452
	21st to end	Day	12% 11% 31% 30% 13% 3	460
May	1st to 10th	Day	12% 10% 26% 32% 16% 5%	463
	11th to 20th	Day	9% 5% 27% 30% 19% 10%	487
	21st to end	Day	10% 6% 19% 31% 18% 16%	529
June	1st to 10th	Day	12% 5% 15% 33% 22% 13%	490
	11th to 20th	Day	7% 4 16% 24% 29% 21%	490
	21st to end	Day	8% 4 12% 26% 33% 18%	486
July	1st to 10th	Day	9% 2 7% 25% 36% 22%	445
	11th to 20th	Day	6% 2 7% 22% 32% 31%	444
	21st to end	Day	6% 2 8% 22% 36% 27%	488
August	1st to 10th	Day	6% 2 7% 27% 31% 26%	446
	11th to 20th	Day	9% 2 6% 30% 35% 19%	439
	21st to end	Day	14% 4 9% 24% 31% 19%	495
September	1st to 10th	Day	8% 4 10% 31% 31% 16%	450
	11th to 20th	Day	11% 6% 13% 26% 33% 12%	450
	21st to end	Day	11% 3 16% 30% 32% 8%	450
October	1st to 10th	Day	11% 5% 22% 32% 24% 6%	450
	11th to 20th	Day	12% 6% 26% 32% 22% 1	450
	21st to end	Day	19% 13% 23% 30% 14% 2	325
November	1st to 10th	Day	17% 9% 32% 27% 10% 4	270
	11th to 20th	Day	17% 14% 39% 24% 6%	270
	21st to end	Day	15% 16% 37% 21% 10% 1	270
December	1st to 10th	Day	28% 17% 28% 23% 3	270
	11th to 20th	Day	24% 18% 36% 15% 6% 1	270
	21st to end	Day	26% 19% 32% 19% 4	297
January	1st to 10th	Night	21% 15% 35% 23% 5%	760
	11th to 20th	Night	21% 18% 29% 24% 8%	760
	21st to end	Night	19% 16% 35% 26% 3	836
February	1st to 10th	Night	22% 10% 35% 29% 4	760
	11th to 20th	Night	25% 13% 32% 25% 4	743
	21st to end	Night	21% 16% 36% 24% 2	628
March	1st to 10th	Night	19% 13% 31% 32% 5%	760
	11th to 20th	Night	17% 13% 35% 25% 9% 1	760
	21st to end	Night	16% 12% 34% 27% 10%	741
April	1st to 10th	Night	13% 11% 34% 29% 13%	570
	11th to 20th	Night	15% 11% 31% 29% 13% 2	563
	21st to end	Night	12% 8% 28% 34% 16% 2	570
May	1st to 10th	Night	9% 7% 28% 31% 22% 3	570
	11th to 20th	Night	10% 4 22% 34% 27% 4	561
	21st to end	Night	7% 2 12% 35% 37% 7%	617
June	1st to 10th	Night	9% 2 10% 40% 34% 6%	570
	11th to 20th	Night	5% 1 11% 28% 43% 13%	570
	21st to end	Night	5% 1 9% 29% 44% 12%	567
July	1st to 10th	Night	7% 1 5% 25% 46% 15%	525
	11th to 20th	Night	6% 4 21% 48% 21%	522
	21st to end	Night	6% 1 6% 25% 47% 15%	591
August	1st to 10th	Night	5% 1 4 25% 48% 18%	537
	11th to 20th	Night	8% 2 6% 29% 47% 8%	534
	21st to end	Night	12% 3 6% 26% 41% 12%	594
September	1st to 10th	Night	9% 3 7% 31% 41% 9%	566
	11th to 20th	Night	12% 3 13% 29% 38% 6%	720
	21st to end	Night	9% 1 15% 32% 39% 3	720
October	1st to 10th	Night	9% 4 22% 32% 28% 6%	720
	11th to 20th	Night	11% 6% 23% 34% 23% 2	720
	21st to end	Night	16% 7% 21% 33% 21% 2	792
November	1st to 10th	Night	12% 8% 20% 37% 19% 4	740
	11th to 20th	Night	14% 9% 28% 34% 13% 1	760
	21st to end	Night	15% 10% 29% 33% 12% 1	760
December	1st to 10th	Night	21% 12% 26% 30% 9% 1	760
	11th to 20th	Night	24% 10% 29% 27% 9%	760
	21st to end	Night	24% 12% 30% 28% 7%	836

Page generated at 2024-06-26 21:18:44. Version ac07

Copyright © 2024 Attilla Danko.