Droop Mountain Battlefield State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Droop Mountain Battlefield State Park 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	14% 8% 3 7% 5% 5% 5% 4 6% 7% 35%	100714
	Night	14% 7% 3 7% 5% 5% 5% 4 6% 7% 38%	98242
Transparency	Day	45% 8% 12% 20% 12% 3	104376
	Night	43% 7% 13% 21% 12% 3	102719
Seeing	Day	23% 15% 24% 21% 12% 5%	15010
	Night	20% 14% 21% 29% 15% 2	25307

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	15% 13% 4 8% 6% 5% 4 3 5% 6% 32%	2836
	11th to 20th	Day	13% 11% 7% 15% 6% 5% 4 3 3 4 27%	2840
	21st to end	Day	19% 12% 4 8% 4 4 3 3 5% 5% 32%	3124
February	1st to 10th	Day	13% 9% 4 8% 6% 4 5% 3 4 6% 36%	1710
	11th to 20th	Day	16% 8% 3 9% 6% 5% 5% 4 5% 7% 33%	1702
	21st to end	Day	19% 11% 4 8% 4 4 4 4 5% 5% 34%	1618
March	1st to 10th	Day	21% 8% 4 6% 4 4 4 3 6% 7% 32%	3435
	11th to 20th	Day	12% 7% 3 6% 4 4 4 3 5% 6% 47%	3480
	21st to end	Day	14% 10% 3 8% 5% 5% 4 4 5% 6% 35%	3815
April	1st to 10th	Day	12% 9% 3 8% 5% 5% 4 3 6% 6% 39%	2156
	11th to 20th	Day	14% 7% 3 7% 4 4 5% 3 5% 6% 41%	2254
	21st to end	Day	18% 7% 3 6% 5% 5% 5% 5% 5% 7% 35%	2454
May	1st to 10th	Day	19% 8% 3 9% 6% 6% 5% 4 6% 6% 27%	4082
	11th to 20th	Day	22% 8% 3 7% 5% 5% 5% 4 6% 8% 28%	4081
	21st to end	Day	10% 5% 2 7% 5% 7% 6% 5% 7% 10% 35%	4476
June	1st to 10th	Day	14% 6% 2 6% 5% 5% 6% 5% 6% 9% 36%	2470
	11th to 20th	Day	11% 5% 2 8% 6% 6% 7% 6% 7% 9% 34%	2470
	21st to end	Day	10% 6% 2 6% 5% 6% 6% 5% 7% 8% 37%	2470
July	1st to 10th	Day	8% 5% 2 6% 6% 5% 6% 6% 7% 9% 40%	4120
	11th to 20th	Day	8% 5% 2 6% 5% 6% 7% 5% 7% 10% 38%	4120
	21st to end	Day	15% 9% 3 9% 7% 6% 6% 5% 7% 8% 25%	4466
August	1st to 10th	Day	13% 6% 2 8% 5% 6% 7% 5% 8% 10% 28%	4104
	11th to 20th	Day	10% 5% 2 8% 7% 6% 8% 5% 7% 8% 32%	4044
	21st to end	Day	7% 5% 2 6% 5% 5% 6% 4 7% 10% 44%	4258
September	1st to 10th	Day	14% 5% 2 7% 4 4 5% 5% 6% 8% 41%	2236
	11th to 20th	Day	14% 6% 3 6% 5% 5% 5% 4 6% 8% 39%	2090
	21st to end	Day	24% 6% 2 6% 4 4 5% 3 6% 6% 34%	2090
October	1st to 10th	Day	17% 5% 2 6% 4 4 4 2 5% 6% 45%	1919
	11th to 20th	Day	16% 7% 3 6% 4 4 3 3 4 5% 45%	1900
	21st to end	Day	15% 8% 2 6% 4 3 4 2 4 6% 45%	2090
November	1st to 10th	Day	11% 7% 2 5% 4 4 3 3 5% 6% 50%	1878
	11th to 20th	Day	14% 7% 2 7% 5% 5% 3 4 6% 6% 42%	1710
	21st to end	Day	14% 7% 2 6% 5% 4 5% 4 5% 6% 41%	1598
December	1st to 10th	Day	18% 12% 4 8% 5% 5% 4 3 6% 7% 29%	1520
	11th to 20th	Day	15% 9% 3 7% 4 4 4 4 4 6% 41%	1974
	21st to end	Day	19% 12% 4 7% 6% 5% 5% 4 6% 8% 26%	3124
January	1st to 10th	Night	11% 10% 5% 10% 6% 6% 7% 5% 7% 6% 26%	4109
	11th to 20th	Night	15% 11% 4 10% 6% 4 4 3 4 4 35%	4120
	21st to end	Night	21% 11% 4 7% 5% 5% 3 3 4 6% 32%	4532
February	1st to 10th	Night	12% 7% 3 10% 5% 4 5% 5% 6% 8% 35%	2470
	11th to 20th	Night	17% 8% 2 8% 7% 5% 5% 4 6% 6% 32%	2361
	21st to end	Night	16% 8% 4 9% 5% 3 4 4 6% 7% 34%	1834
March	1st to 10th	Night	22% 11% 4 7% 4 5% 5% 4 5% 5% 28%	3418
	11th to 20th	Night	10% 4 3 9% 5% 5% 5% 4 5% 6% 44%	3480
	21st to end	Night	15% 7% 2 5% 4 3 4 3 6% 7% 41%	3817
April	1st to 10th	Night	13% 9% 2 7% 6% 4 4 4 6% 8% 38%	2024
	11th to 20th	Night	12% 6% 3 6% 4 5% 4 4 6% 8% 40%	1875
	21st to end	Night	14% 6% 2 6% 4 4 5% 4 6% 8% 41%	1743
May	1st to 10th	Night	21% 10% 3 7% 5% 5% 4 4 5% 7% 29%	2813
	11th to 20th	Night	24% 10% 2 6% 4 3 3 3 5% 7% 32%	2812
	21st to end	Night	11% 5% 2 7% 5% 5% 6% 4 8% 9% 38%	3079
June	1st to 10th	Night	9% 6% 2 6% 4 5% 4 5% 7% 10% 43%	1710
	11th to 20th	Night	11% 5% 2 6% 4 4 4 4 7% 10% 43%	1710
	21st to end	Night	9% 5% 1 5% 5% 4 4 5% 7% 10% 44%	1710
July	1st to 10th	Night	7% 4 2 6% 5% 4 6% 6% 7% 10% 42%	2840
	11th to 20th	Night	8% 5% 2 6% 4 4 4 5% 6% 10% 46%	2840
	21st to end	Night	12% 9% 3 9% 5% 6% 6% 4 7% 8% 31%	3087
August	1st to 10th	Night	14% 6% 2 7% 5% 5% 5% 4 6% 8% 36%	2825
	11th to 20th	Night	12% 5% 2 7% 6% 6% 6% 4 7% 8% 36%	2785
	21st to end	Night	8% 5% 2 5% 4 4 4 3 6% 8% 52%	3364
September	1st to 10th	Night	13% 5% 2 6% 4 4 5% 4 6% 7% 46%	1940
	11th to 20th	Night	15% 5% 2 5% 3 3 4 4 4 7% 46%	2090
	21st to end	Night	21% 7% 2 5% 4 4 4 4 5% 5% 39%	2090
October	1st to 10th	Night	15% 6% 2 5% 4 5% 4 3 5% 6% 47%	2259
	11th to 20th	Night	13% 8% 2 6% 5% 4 4 3 4 6% 45%	2280
	21st to end	Night	14% 6% 1 6% 4 4 5% 3 6% 6% 45%	2508
November	1st to 10th	Night	11% 7% 3 6% 4 3 4 4 5% 7% 46%	2268
	11th to 20th	Night	14% 5% 3 5% 3 5% 5% 5% 7% 7% 40%	2470
	21st to end	Night	13% 6% 2 6% 4 5% 5% 4 6% 7% 40%	2575
December	1st to 10th	Night	18% 9% 4 8% 6% 5% 5% 4 5% 6% 30%	2660
	11th to 20th	Night	14% 7% 4 9% 6% 5% 5% 3 5% 6% 35%	3212
	21st to end	Night	18% 8% 6% 7% 6% 5% 6% 5% 6% 6% 28%	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	54% 4 8% 23% 11% 1	2837
	11th to 20th	Day	61% 4 9% 14% 10% 2	2840
	21st to end	Day	54% 4 12% 17% 12% 1	3124
February	1st to 10th	Day	50% 6% 11% 20% 12% 2	1710
	11th to 20th	Day	52% 5% 10% 18% 12% 2	1711
	21st to end	Day	52% 7% 9% 16% 13% 3	1618
March	1st to 10th	Day	51% 7% 11% 22% 9% 2	3435
	11th to 20th	Day	39% 5% 12% 22% 19% 3	3480
	21st to end	Day	51% 6% 9% 18% 13% 3	3815
April	1st to 10th	Day	45% 6% 11% 19% 14% 4	2156
	11th to 20th	Day	44% 6% 10% 21% 16% 3	2254
	21st to end	Day	48% 6% 13% 20% 11% 2	2454
May	1st to 10th	Day	55% 9% 10% 17% 9% 1	4120
	11th to 20th	Day	52% 10% 12% 18% 7% 1	4085
	21st to end	Day	40% 11% 15% 19% 11% 4	4489
June	1st to 10th	Day	43% 10% 13% 21% 13%	2470
	11th to 20th	Day	44% 9% 14% 17% 14%	2470
	21st to end	Day	41% 11% 14% 21% 11% 2	2470
July	1st to 10th	Day	38% 12% 19% 19% 8% 5%	4055
	11th to 20th	Day	36% 11% 16% 26% 10% 1	4051
	21st to end	Day	54% 10% 11% 17% 7% 1	4324
August	1st to 10th	Day	45% 12% 17% 18% 7%	4091
	11th to 20th	Day	43% 12% 14% 20% 11%	4083
	21st to end	Day	33% 10% 16% 27% 11% 1	4258
September	1st to 10th	Day	40% 8% 11% 19% 17% 4	2236
	11th to 20th	Day	43% 7% 9% 22% 18% 2	2090
	21st to end	Day	50% 7% 10% 17% 15% 2	2090
October	1st to 10th	Day	28% 7% 11% 20% 26% 8%	3192
	11th to 20th	Day	30% 6% 11% 24% 14% 15%	3140
	21st to end	Day	28% 4 10% 31% 14% 12%	3428
November	1st to 10th	Day	36% 6% 11% 23% 21% 4	1878
	11th to 20th	Day	42% 5% 12% 19% 18% 4	1710
	21st to end	Day	42% 5% 15% 21% 15% 2	1598
December	1st to 10th	Day	54% 6% 12% 16% 10% 2	1520
	11th to 20th	Day	46% 4 11% 21% 16% 2	1970
	21st to end	Day	56% 5% 11% 19% 8% 1	3124
January	1st to 10th	Night	57% 4 12% 15% 11% 1	4109
	11th to 20th	Night	53% 4 10% 19% 12% 2	4120
	21st to end	Night	55% 4 11% 20% 9% 1	4532
February	1st to 10th	Night	46% 7% 15% 19% 12% 1	2470
	11th to 20th	Night	52% 6% 12% 17% 11% 2	2363
	21st to end	Night	49% 7% 13% 19% 8% 4	1834
March	1st to 10th	Night	56% 7% 8% 18% 9% 2	3418
	11th to 20th	Night	42% 5% 10% 27% 16% 1	3480
	21st to end	Night	41% 7% 12% 20% 15% 3	3817
April	1st to 10th	Night	46% 7% 13% 19% 14% 3	2024
	11th to 20th	Night	41% 7% 14% 20% 15% 4	1875
	21st to end	Night	41% 7% 15% 25% 12% 1	1743
May	1st to 10th	Night	55% 8% 12% 17% 8% 1	2840
	11th to 20th	Night	52% 8% 15% 19% 6% 1	2813
	21st to end	Night	40% 11% 19% 21% 5% 4	3087
June	1st to 10th	Night	35% 12% 17% 23% 13%	1710
	11th to 20th	Night	35% 10% 19% 22% 11% 1	1710
	21st to end	Night	32% 13% 18% 25% 12% 1	1710
July	1st to 10th	Night	33% 13% 19% 21% 11% 3	2795
	11th to 20th	Night	31% 11% 20% 30% 8% 1	2786
	21st to end	Night	46% 12% 14% 20% 7%	2988
August	1st to 10th	Night	43% 11% 17% 23% 5%	2814
	11th to 20th	Night	40% 12% 16% 21% 11% 1	2812
	21st to end	Night	29% 9% 16% 32% 13% 1	3364
September	1st to 10th	Night	37% 8% 15% 19% 17% 4	1940
	11th to 20th	Night	37% 7% 11% 24% 19% 2	2090
	21st to end	Night	46% 8% 11% 22% 13% 1	2090
October	1st to 10th	Night	33% 6% 9% 24% 24% 4	3766
	11th to 20th	Night	31% 9% 10% 19% 19% 12%	3779
	21st to end	Night	26% 4 12% 28% 19% 11%	4120
November	1st to 10th	Night	38% 6% 12% 19% 20% 5%	2268
	11th to 20th	Night	40% 6% 13% 20% 17% 4	2470
	21st to end	Night	43% 5% 13% 20% 15% 3	2575
December	1st to 10th	Night	54% 6% 13% 17% 9% 2	2660
	11th to 20th	Night	51% 4 12% 19% 13% 1	3215
	21st to end	Night	55% 6% 11% 18% 9%	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	37% 27% 23% 9% 4 1	270
	11th to 20th	Day	39% 27% 26% 9% 1	270
	21st to end	Day	40% 24% 24% 9% 3	297
February	1st to 10th	Day	33% 26% 27% 11% 3	270
	11th to 20th	Day	47% 25% 19% 7% 1	270
	21st to end	Day	41% 26% 25% 8% 1	273
March	1st to 10th	Day	32% 25% 22% 16% 5% 1	460
	11th to 20th	Day	31% 27% 23% 15% 4 1	460
	21st to end	Day	27% 26% 26% 16% 5%	506
April	1st to 10th	Day	27% 27% 22% 15% 8% 1	460
	11th to 20th	Day	21% 21% 29% 17% 8% 3	452
	21st to end	Day	28% 19% 27% 14% 8% 2	460
May	1st to 10th	Day	28% 18% 29% 13% 9% 3	463
	11th to 20th	Day	24% 14% 28% 19% 11% 4	487
	21st to end	Day	16% 11% 23% 27% 15% 8%	529
June	1st to 10th	Day	17% 12% 27% 23% 14% 7%	490
	11th to 20th	Day	11% 12% 29% 25% 15% 8%	490
	21st to end	Day	11% 12% 32% 24% 14% 6%	490
July	1st to 10th	Day	14% 7% 21% 25% 20% 13%	485
	11th to 20th	Day	6% 6% 24% 36% 18% 10%	484
	21st to end	Day	14% 6% 26% 29% 16% 10%	532
August	1st to 10th	Day	18% 6% 21% 27% 18% 10%	486
	11th to 20th	Day	14% 8% 20% 27% 19% 12%	479
	21st to end	Day	10% 5% 21% 27% 22% 15%	539
September	1st to 10th	Day	14% 7% 20% 27% 20% 12%	490
	11th to 20th	Day	16% 5% 17% 30% 24% 9%	490
	21st to end	Day	24% 14% 21% 23% 14% 4	490
October	1st to 10th	Day	19% 9% 24% 26% 18% 4	490
	11th to 20th	Day	22% 14% 24% 24% 13% 3	490
	21st to end	Day	25% 16% 24% 22% 12% 2	539
November	1st to 10th	Day	19% 16% 27% 24% 12% 2	458
	11th to 20th	Day	35% 16% 26% 18% 5%	270
	21st to end	Day	27% 20% 32% 15% 5% 1	216
December	1st to 10th	Day	34% 24% 23% 12% 4 2	180
	11th to 20th	Day	30% 24% 23% 17% 6% 1	198
	21st to end	Day	32% 25% 23% 15% 4 1	297
January	1st to 10th	Night	30% 24% 25% 17% 4	760
	11th to 20th	Night	29% 21% 28% 19% 3	760
	21st to end	Night	29% 22% 28% 20% 2	836
February	1st to 10th	Night	26% 21% 27% 24% 3	760
	11th to 20th	Night	30% 27% 26% 15% 1	743
	21st to end	Night	28% 22% 30% 18% 1	628
March	1st to 10th	Night	24% 21% 29% 23% 3	760
	11th to 20th	Night	27% 22% 24% 21% 6%	760
	21st to end	Night	23% 19% 29% 22% 6%	836
April	1st to 10th	Night	22% 21% 27% 24% 5%	760
	11th to 20th	Night	19% 16% 24% 28% 12% 1	751
	21st to end	Night	20% 13% 26% 33% 8% 1	603
May	1st to 10th	Night	20% 12% 24% 30% 12% 1	570
	11th to 20th	Night	22% 10% 19% 33% 15%	561
	21st to end	Night	15% 5% 16% 32% 28% 4	617
June	1st to 10th	Night	10% 6% 17% 38% 26% 2	570
	11th to 20th	Night	12% 6% 14% 36% 30% 2	570
	21st to end	Night	10% 4 17% 40% 27% 2	570
July	1st to 10th	Night	12% 3 10% 37% 33% 6%	555
	11th to 20th	Night	7% 3 9% 36% 39% 6%	552
	21st to end	Night	7% 6% 10% 38% 35% 4	624
August	1st to 10th	Night	16% 2 9% 37% 33% 3	567
	11th to 20th	Night	13% 4 9% 36% 34% 4	564
	21st to end	Night	13% 3 9% 36% 34% 6%	763
September	1st to 10th	Night	14% 4 11% 36% 29% 6%	760
	11th to 20th	Night	17% 6% 11% 32% 30% 4	760
	21st to end	Night	24% 7% 16% 29% 22% 2	760
October	1st to 10th	Night	18% 9% 16% 31% 23% 3	760
	11th to 20th	Night	18% 16% 20% 28% 16% 1	760
	21st to end	Night	20% 14% 20% 32% 13% 1	836
November	1st to 10th	Night	17% 12% 23% 33% 14% 1	755
	11th to 20th	Night	25% 13% 21% 30% 10% 1	760
	21st to end	Night	22% 17% 24% 31% 7% 1	760
December	1st to 10th	Night	27% 22% 25% 21% 5%	760
	11th to 20th	Night	22% 20% 28% 26% 4	760
	21st to end	Night	29% 15% 26% 27% 4	836

Page generated at 2024-11-01 22:47:43. Version ac07

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