Belleplain State Forest
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Belleplain State Forest 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% 7% 2 6% 4 4 4 4 6% 8% 41%	101210
	Night	15% 7% 2 6% 4 4 4 3 5% 7% 42%	97783
Transparency	Day	38% 7% 13% 24% 15% 3	104782
	Night	40% 6% 12% 23% 16% 3	102298
Seeing	Day	17% 13% 29% 27% 12% 3	15110
	Night	18% 13% 29% 27% 12% 1	24378

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	15% 9% 2 5% 3 3 4 3 4 5% 48%	2517
	11th to 20th	Day	15% 8% 3 7% 5% 4 4 3 4 5% 41%	2598
	21st to end	Day	21% 10% 3 7% 4 3 3 3 4 5% 36%	3124
February	1st to 10th	Day	14% 8% 2 7% 4 4 4 4 6% 7% 40%	1712
	11th to 20th	Day	17% 7% 3 6% 3 4 4 3 6% 6% 42%	1848
	21st to end	Day	17% 10% 2 8% 4 4 4 3 5% 5% 38%	1570
March	1st to 10th	Day	25% 7% 2 4 3 3 3 2 4 6% 39%	3116
	11th to 20th	Day	10% 4 2 4 4 3 5% 4 7% 7% 51%	3443
	21st to end	Day	19% 8% 2 5% 4 3 4 3 4 5% 42%	4066
April	1st to 10th	Day	15% 7% 3 6% 3 4 4 4 5% 7% 43%	2280
	11th to 20th	Day	13% 6% 2 4 3 4 4 4 5% 8% 47%	2254
	21st to end	Day	15% 6% 2 5% 4 3 4 4 7% 9% 41%	2280
May	1st to 10th	Day	22% 9% 3 6% 5% 4 3 4 6% 8% 28%	3980
	11th to 20th	Day	24% 9% 3 6% 4 4 4 3 5% 7% 31%	4353
	21st to end	Day	10% 5% 2 5% 4 4 4 4 6% 9% 45%	4837
June	1st to 10th	Day	10% 6% 2 6% 4 4 4 6% 7% 9% 42%	2660
	11th to 20th	Day	10% 5% 2 6% 4 4 5% 5% 7% 10% 42%	2660
	21st to end	Day	10% 5% 1 4 3 5% 5% 5% 7% 11% 44%	2660
July	1st to 10th	Day	6% 5% 2 5% 5% 6% 6% 5% 8% 13% 38%	4440
	11th to 20th	Day	12% 4 2 6% 4 5% 5% 5% 8% 12% 38%	4440
	21st to end	Day	10% 6% 3 8% 6% 6% 6% 5% 9% 10% 31%	4724
August	1st to 10th	Day	16% 6% 2 5% 4 4 5% 4 6% 11% 36%	4022
	11th to 20th	Day	10% 6% 2 7% 4 6% 6% 4 7% 10% 40%	3730
	21st to end	Day	9% 5% 2 5% 4 4 5% 4 8% 9% 45%	4180
September	1st to 10th	Day	14% 5% 2 6% 4 4 4 4 6% 8% 44%	2280
	11th to 20th	Day	11% 5% 3 6% 4 4 3 3 6% 7% 48%	2230
	21st to end	Day	17% 8% 3 7% 4 4 5% 3 5% 7% 37%	2090
October	1st to 10th	Day	15% 7% 3 5% 3 4 4 2 5% 7% 45%	1938
	11th to 20th	Day	15% 5% 2 5% 3 3 3 2 4 6% 51%	1900
	21st to end	Day	14% 6% 2 6% 4 4 4 2 4 5% 48%	2019
November	1st to 10th	Day	13% 6% 2 4 3 4 4 3 5% 6% 51%	1698
	11th to 20th	Day	14% 6% 2 5% 3 3 3 3 5% 7% 47%	1710
	21st to end	Day	14% 5% 2 5% 4 4 4 3 4 7% 47%	1653
December	1st to 10th	Day	17% 8% 2 5% 3 3 6% 3 5% 7% 39%	1520
	11th to 20th	Day	18% 8% 2 5% 4 3 3 3 4 5% 45%	1906
	21st to end	Day	15% 7% 2 5% 4 4 4 4 6% 8% 41%	2772
January	1st to 10th	Night	16% 7% 2 5% 3 3 4 3 5% 6% 46%	4429
	11th to 20th	Night	18% 9% 2 6% 3 3 3 3 4 5% 44%	4344
	21st to end	Night	20% 9% 3 6% 5% 3 3 3 4 5% 38%	4532
February	1st to 10th	Night	16% 6% 3 6% 4 4 4 4 4 5% 43%	2466
	11th to 20th	Night	18% 7% 2 6% 4 4 3 4 5% 5% 42%	2218
	21st to end	Night	17% 7% 3 5% 4 4 3 3 5% 5% 44%	1884
March	1st to 10th	Night	22% 11% 3 6% 4 3 3 2 3 6% 37%	3724
	11th to 20th	Night	12% 6% 2 5% 4 4 4 4 5% 6% 47%	3511
	21st to end	Night	18% 10% 3 6% 3 3 3 2 3 4 43%	3564
April	1st to 10th	Night	17% 9% 3 6% 3 3 4 4 5% 6% 41%	1900
	11th to 20th	Night	13% 6% 2 7% 5% 4 4 3 5% 6% 44%	1875
	21st to end	Night	17% 6% 2 5% 4 4 5% 3 5% 6% 41%	1900
May	1st to 10th	Night	17% 10% 4 10% 5% 5% 4 3 5% 7% 29%	2947
	11th to 20th	Night	24% 10% 3 6% 5% 5% 5% 3 4 5% 30%	2569
	21st to end	Night	12% 8% 2 6% 4 5% 5% 4 5% 8% 40%	2738
June	1st to 10th	Night	13% 7% 2 7% 4 3 4 4 6% 8% 41%	1520
	11th to 20th	Night	10% 5% 2 6% 5% 5% 6% 4 6% 10% 42%	1520
	21st to end	Night	8% 5% 2 6% 5% 5% 4 5% 7% 10% 41%	1520
July	1st to 10th	Night	8% 6% 3 7% 5% 6% 6% 5% 7% 9% 37%	2520
	11th to 20th	Night	11% 6% 3 7% 4 5% 4 5% 7% 10% 40%	2520
	21st to end	Night	14% 9% 3 7% 5% 5% 6% 5% 7% 8% 31%	2824
August	1st to 10th	Night	19% 8% 3 6% 5% 4 5% 4 5% 9% 31%	2875
	11th to 20th	Night	10% 6% 2 7% 4 4 5% 4 7% 8% 43%	3097
	21st to end	Night	9% 4 2 5% 4 3 4 4 5% 8% 52%	3476
September	1st to 10th	Night	14% 7% 2 5% 5% 4 4 3 5% 7% 44%	1900
	11th to 20th	Night	10% 6% 2 5% 3 3 3 4 5% 8% 51%	1949
	21st to end	Night	19% 8% 2 6% 3 4 4 3 4 7% 39%	2090
October	1st to 10th	Night	16% 7% 2 6% 4 4 3 3 5% 6% 44%	2237
	11th to 20th	Night	16% 5% 2 5% 2 2 3 2 5% 6% 52%	2280
	21st to end	Night	14% 7% 2 5% 3 3 4 3 4 6% 48%	2577
November	1st to 10th	Night	12% 6% 2 4 3 3 4 3 5% 6% 52%	2453
	11th to 20th	Night	15% 7% 2 6% 4 4 4 3 4 5% 48%	2470
	21st to end	Night	12% 5% 2 5% 5% 4 4 4 5% 7% 48%	2522
December	1st to 10th	Night	18% 9% 2 6% 4 4 3 3 5% 6% 40%	2660
	11th to 20th	Night	17% 6% 2 5% 4 4 4 3 5% 7% 42%	3288
	21st to end	Night	15% 8% 3 7% 4 4 4 4 6% 7% 38%	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	39% 3 12% 28% 15% 3	2518
	11th to 20th	Day	44% 5% 12% 22% 14% 4	2598
	21st to end	Day	48% 8% 9% 20% 12% 2	3124
February	1st to 10th	Day	42% 5% 14% 25% 13% 1	1712
	11th to 20th	Day	42% 4 10% 25% 15% 4	1857
	21st to end	Day	46% 5% 10% 20% 14% 5%	1570
March	1st to 10th	Day	46% 4 9% 26% 12% 4	3119
	11th to 20th	Day	28% 6% 11% 32% 20% 4	3443
	21st to end	Day	44% 5% 8% 19% 19% 5%	4066
April	1st to 10th	Day	39% 7% 12% 19% 18% 5%	2280
	11th to 20th	Day	35% 6% 13% 23% 18% 4	2254
	21st to end	Day	38% 7% 13% 19% 19% 4	2280
May	1st to 10th	Day	53% 9% 11% 17% 9% 2	3992
	11th to 20th	Day	50% 9% 15% 17% 8% 1	4357
	21st to end	Day	34% 8% 15% 24% 18% 1	4837
June	1st to 10th	Day	35% 11% 14% 23% 15% 2	2660
	11th to 20th	Day	34% 12% 14% 26% 13% 2	2660
	21st to end	Day	31% 10% 16% 24% 18% 1	2660
July	1st to 10th	Day	36% 12% 18% 20% 12% 2	4370
	11th to 20th	Day	37% 8% 20% 26% 8% 1	4365
	21st to end	Day	43% 9% 13% 21% 13% 1	4573
August	1st to 10th	Day	41% 7% 18% 25% 9%	4009
	11th to 20th	Day	38% 7% 14% 30% 10% 1	3766
	21st to end	Day	32% 7% 12% 30% 16% 2	4180
September	1st to 10th	Day	36% 8% 15% 21% 18% 3	2280
	11th to 20th	Day	34% 6% 10% 24% 22% 3	2230
	21st to end	Day	45% 7% 10% 17% 18% 2	2090
October	1st to 10th	Day	33% 4 9% 23% 25% 5%	3224
	11th to 20th	Day	25% 3 8% 27% 29% 9%	3140
	21st to end	Day	26% 3 12% 29% 23% 7%	3309
November	1st to 10th	Day	34% 4 13% 29% 17% 3	1698
	11th to 20th	Day	37% 5% 11% 23% 23% 3	1710
	21st to end	Day	37% 5% 11% 29% 15% 3	1653
December	1st to 10th	Day	43% 6% 16% 20% 13% 2	1520
	11th to 20th	Day	41% 4 11% 28% 12% 3	1906
	21st to end	Day	39% 7% 16% 24% 14% 1	2772
January	1st to 10th	Night	39% 4 10% 28% 15% 4	4429
	11th to 20th	Night	43% 4 11% 25% 15% 2	4344
	21st to end	Night	47% 4 9% 25% 13% 2	4532
February	1st to 10th	Night	42% 5% 13% 23% 14% 2	2466
	11th to 20th	Night	44% 4 9% 19% 19% 5%	2220
	21st to end	Night	42% 5% 9% 22% 17% 4	1884
March	1st to 10th	Night	49% 4 9% 23% 13% 2	3734
	11th to 20th	Night	37% 6% 11% 26% 16% 5%	3512
	21st to end	Night	46% 4 8% 16% 21% 6%	3564
April	1st to 10th	Night	43% 5% 10% 19% 19% 5%	1900
	11th to 20th	Night	40% 6% 9% 20% 20% 4	1875
	21st to end	Night	42% 7% 9% 18% 19% 5%	1900
May	1st to 10th	Night	53% 7% 9% 21% 9% 1	2953
	11th to 20th	Night	56% 6% 11% 16% 9% 1	2570
	21st to end	Night	40% 8% 17% 18% 15% 3	2739
June	1st to 10th	Night	40% 7% 13% 21% 18% 1	1520
	11th to 20th	Night	37% 9% 12% 27% 14% 2	1520
	21st to end	Night	35% 9% 14% 26% 13% 3	1520
July	1st to 10th	Night	42% 10% 17% 20% 10% 1	2480
	11th to 20th	Night	38% 8% 20% 26% 8% 1	2472
	21st to end	Night	48% 7% 15% 16% 13% 1	2734
August	1st to 10th	Night	49% 7% 17% 19% 8%	2864
	11th to 20th	Night	36% 8% 14% 31% 11% 1	3127
	21st to end	Night	30% 6% 11% 28% 22% 2	3476
September	1st to 10th	Night	39% 7% 11% 21% 18% 4	1900
	11th to 20th	Night	31% 7% 12% 25% 22% 3	1949
	21st to end	Night	46% 5% 9% 20% 17% 2	2090
October	1st to 10th	Night	38% 4 10% 24% 21% 3	3731
	11th to 20th	Night	24% 3 12% 24% 29% 8%	3779
	21st to end	Night	24% 3 13% 29% 24% 6%	4237
November	1st to 10th	Night	33% 5% 11% 26% 19% 5%	2453
	11th to 20th	Night	39% 5% 10% 20% 21% 5%	2470
	21st to end	Night	35% 5% 12% 26% 18% 2	2522
December	1st to 10th	Night	45% 6% 12% 22% 13% 2	2660
	11th to 20th	Night	40% 5% 12% 21% 19% 3	3288
	21st to end	Night	42% 6% 16% 24% 10% 1	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	18% 26% 33% 17% 5% 1	180
	11th to 20th	Day	21% 30% 31% 16% 3	204
	21st to end	Day	22% 22% 32% 21% 3 1	297
February	1st to 10th	Day	22% 18% 42% 15% 3	272
	11th to 20th	Day	25% 24% 37% 13% 1	456
	21st to end	Day	24% 25% 31% 15% 4	382
March	1st to 10th	Day	18% 24% 35% 19% 3	460
	11th to 20th	Day	20% 23% 35% 18% 3 2	460
	21st to end	Day	21% 17% 38% 21% 2 1	506
April	1st to 10th	Day	19% 21% 37% 17% 5% 1	460
	11th to 20th	Day	15% 19% 35% 25% 6% 1	452
	21st to end	Day	21% 14% 37% 23% 5%	460
May	1st to 10th	Day	24% 13% 33% 23% 5% 2	463
	11th to 20th	Day	22% 10% 33% 27% 7% 1	487
	21st to end	Day	18% 5% 22% 35% 17% 3	529
June	1st to 10th	Day	12% 7% 32% 30% 16% 3	490
	11th to 20th	Day	12% 6% 28% 38% 14% 2	490
	21st to end	Day	12% 4 29% 38% 16% 2	490
July	1st to 10th	Day	11% 5% 21% 36% 21% 6%	485
	11th to 20th	Day	6% 2 19% 41% 26% 6%	484
	21st to end	Day	11% 4 23% 38% 21% 3	532
August	1st to 10th	Day	12% 5% 20% 36% 22% 4	486
	11th to 20th	Day	11% 3 18% 37% 25% 6%	479
	21st to end	Day	10% 5% 22% 33% 21% 9%	539
September	1st to 10th	Day	17% 6% 21% 30% 19% 9%	490
	11th to 20th	Day	13% 4 29% 29% 19% 6%	490
	21st to end	Day	22% 10% 26% 29% 11% 2	490
October	1st to 10th	Day	20% 8% 23% 29% 14% 6%	490
	11th to 20th	Day	17% 14% 24% 26% 16% 3	490
	21st to end	Day	17% 16% 30% 25% 11% 2	502
November	1st to 10th	Day	16% 15% 30% 23% 13% 3	374
	11th to 20th	Day	16% 21% 34% 22% 8%	370
	21st to end	Day	17% 20% 30% 22% 9% 1	313
December	1st to 10th	Day	24% 21% 34% 17% 5%	180
	11th to 20th	Day	24% 25% 29% 17% 4	180
	21st to end	Day	23% 20% 31% 19% 7% 1	198
January	1st to 10th	Night	20% 24% 34% 17% 5%	760
	11th to 20th	Night	23% 21% 29% 24% 3	760
	21st to end	Night	18% 23% 39% 19% 2	836
February	1st to 10th	Night	20% 18% 36% 23% 2	760
	11th to 20th	Night	25% 25% 34% 15% 1	743
	21st to end	Night	21% 21% 34% 20% 3	628
March	1st to 10th	Night	19% 20% 35% 21% 4	760
	11th to 20th	Night	22% 20% 32% 19% 6% 1	760
	21st to end	Night	21% 14% 38% 21% 5% 1	836
April	1st to 10th	Night	20% 19% 35% 20% 5%	760
	11th to 20th	Night	16% 13% 34% 29% 7%	751
	21st to end	Night	20% 10% 34% 29% 6% 1	760
May	1st to 10th	Night	20% 10% 32% 30% 7%	644
	11th to 20th	Night	19% 8% 31% 33% 9%	422
	21st to end	Night	17% 3 23% 35% 21% 2	411
June	1st to 10th	Night	17% 4 24% 39% 15% 1	380
	11th to 20th	Night	13% 2 26% 38% 20% 1	380
	21st to end	Night	8% 2 23% 48% 18% 2	380
July	1st to 10th	Night	10% 3 19% 44% 21% 2	370
	11th to 20th	Night	8% 2 13% 43% 31% 3	368
	21st to end	Night	9% 3 17% 46% 24% 2	465
August	1st to 10th	Night	12% 4 13% 42% 28% 2	591
	11th to 20th	Night	10% 3 20% 39% 25% 3	750
	21st to end	Night	12% 3 14% 39% 28% 4	836
September	1st to 10th	Night	17% 3 18% 34% 23% 4	760
	11th to 20th	Night	13% 3 21% 32% 26% 5%	760
	21st to end	Night	24% 6% 22% 28% 19% 1	760
October	1st to 10th	Night	20% 7% 22% 28% 19% 4	760
	11th to 20th	Night	18% 13% 24% 29% 16% 1	760
	21st to end	Night	19% 13% 32% 23% 12% 1	836
November	1st to 10th	Night	15% 14% 33% 25% 11% 2	755
	11th to 20th	Night	19% 18% 30% 26% 7% 1	760
	21st to end	Night	15% 19% 33% 22% 10% 1	760
December	1st to 10th	Night	23% 20% 31% 16% 8% 2	760
	11th to 20th	Night	18% 21% 37% 19% 5%	760
	21st to end	Night	19% 18% 34% 26% 3	836

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

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