Half Hollow Hills
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Half Hollow Hills 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	16% 7% 2 6% 4 4 4 4 5% 7% 40%	101234
	Night	18% 7% 3 6% 4 4 4 3 5% 6% 41%	97780
Transparency	Day	41% 6% 13% 22% 15% 2	104792
	Night	43% 5% 12% 23% 15% 2	102311
Seeing	Day	21% 13% 32% 23% 9% 2	15056
	Night	20% 12% 31% 27% 9% 1	24135

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	16% 7% 2 6% 4 4 3 3 4 5% 46%	2517
	11th to 20th	Day	17% 10% 3 5% 4 5% 4 4 5% 5% 38%	2520
	21st to end	Day	21% 12% 5% 8% 4 4 4 2 4 5% 31%	2937
February	1st to 10th	Day	17% 8% 2 6% 4 4 4 3 4 7% 39%	1765
	11th to 20th	Day	14% 7% 2 7% 5% 4 4 3 4 6% 45%	1848
	21st to end	Day	20% 9% 3 6% 4 4 4 3 5% 5% 38%	1570
March	1st to 10th	Day	26% 10% 3 6% 3 3 3 3 4 5% 35%	3116
	11th to 20th	Day	9% 5% 1 5% 5% 5% 5% 4 6% 9% 46%	3275
	21st to end	Day	20% 7% 3 6% 4 3 3 3 4 5% 43%	4166
April	1st to 10th	Day	18% 8% 3 6% 4 3 4 4 5% 8% 38%	2280
	11th to 20th	Day	18% 7% 2 6% 5% 4 4 3 5% 7% 41%	2254
	21st to end	Day	20% 6% 2 5% 4 3 4 3 5% 7% 40%	2342
May	1st to 10th	Day	27% 10% 3 5% 3 3 3 4 5% 8% 31%	4106
	11th to 20th	Day	25% 8% 3 6% 4 4 4 3 5% 7% 32%	4270
	21st to end	Day	14% 6% 2 5% 3 3 4 4 6% 9% 44%	4837
June	1st to 10th	Day	17% 5% 2 5% 5% 4 4 4 7% 9% 39%	2660
	11th to 20th	Day	14% 7% 2 5% 5% 5% 5% 4 6% 8% 39%	2660
	21st to end	Day	11% 6% 3 5% 5% 4 5% 4 6% 8% 43%	2660
July	1st to 10th	Day	9% 7% 2 7% 5% 5% 6% 5% 7% 10% 36%	4440
	11th to 20th	Day	12% 6% 2 6% 4 4 5% 5% 7% 10% 39%	4440
	21st to end	Day	15% 8% 3 7% 5% 5% 5% 5% 7% 8% 33%	4814
August	1st to 10th	Day	18% 7% 3 6% 5% 5% 5% 4 7% 9% 33%	4184
	11th to 20th	Day	11% 7% 2 6% 4 4 5% 4 6% 9% 42%	3730
	21st to end	Day	8% 5% 2 6% 4 4 4 4 6% 10% 47%	4180
September	1st to 10th	Day	14% 6% 1 6% 4 4 4 3 5% 8% 45%	2280
	11th to 20th	Day	12% 5% 2 5% 3 3 4 4 5% 7% 50%	2166
	21st to end	Day	19% 7% 3 6% 4 3 4 3 5% 6% 40%	2090
October	1st to 10th	Day	19% 7% 2 6% 3 3 4 3 5% 7% 41%	2036
	11th to 20th	Day	15% 5% 2 5% 4 4 4 4 5% 7% 47%	1900
	21st to end	Day	19% 6% 2 5% 4 4 4 3 5% 6% 42%	1901
November	1st to 10th	Day	15% 5% 2 5% 3 3 3 3 4 5% 51%	1698
	11th to 20th	Day	18% 7% 2 5% 2 3 3 2 4 7% 48%	1710
	21st to end	Day	14% 7% 2 5% 3 4 4 4 5% 7% 44%	1684
December	1st to 10th	Day	18% 6% 3 6% 4 4 4 4 6% 7% 37%	1520
	11th to 20th	Day	22% 8% 2 4 3 2 2 3 4 5% 46%	1906
	21st to end	Day	18% 10% 2 7% 5% 5% 5% 4 6% 6% 33%	2772
January	1st to 10th	Night	18% 7% 2 5% 4 3 3 3 4 6% 47%	4429
	11th to 20th	Night	17% 9% 3 7% 4 3 3 3 4 4 44%	4440
	21st to end	Night	23% 10% 3 7% 4 4 4 3 4 5% 34%	4715
February	1st to 10th	Night	16% 10% 2 5% 4 3 4 3 5% 5% 42%	2413
	11th to 20th	Night	18% 8% 3 5% 4 4 4 3 5% 6% 41%	2218
	21st to end	Night	20% 7% 3 5% 4 3 3 3 4 6% 42%	1884
March	1st to 10th	Night	23% 12% 3 6% 3 3 3 2 4 5% 36%	3724
	11th to 20th	Night	12% 5% 2 6% 5% 4 5% 4 5% 6% 45%	3679
	21st to end	Night	22% 8% 2 5% 4 3 3 3 4 5% 40%	3466
April	1st to 10th	Night	19% 8% 2 6% 5% 4 4 3 5% 6% 38%	1900
	11th to 20th	Night	18% 8% 3 5% 4 3 4 3 5% 6% 40%	1875
	21st to end	Night	18% 7% 3 6% 4 3 4 3 4 5% 42%	1838
May	1st to 10th	Night	22% 11% 4 8% 4 4 4 3 5% 7% 28%	2834
	11th to 20th	Night	24% 9% 3 7% 5% 4 4 3 4 5% 31%	2638
	21st to end	Night	17% 7% 3 5% 4 4 4 3 5% 8% 41%	2738
June	1st to 10th	Night	18% 7% 2 4 4 5% 3 4 5% 8% 39%	1520
	11th to 20th	Night	14% 7% 2 6% 4 4 4 4 7% 9% 40%	1520
	21st to end	Night	11% 5% 2 7% 5% 4 6% 5% 7% 9% 39%	1520
July	1st to 10th	Night	11% 8% 3 9% 6% 6% 4 5% 7% 7% 33%	2520
	11th to 20th	Night	16% 7% 3 6% 4 4 5% 4 7% 9% 35%	2520
	21st to end	Night	18% 9% 3 6% 4 4 5% 4 6% 8% 33%	2739
August	1st to 10th	Night	23% 7% 3 6% 4 5% 4 4 6% 8% 31%	2709
	11th to 20th	Night	13% 7% 3 7% 4 4 5% 4 7% 8% 39%	3097
	21st to end	Night	8% 5% 2 4 4 4 4 4 5% 8% 52%	3476
September	1st to 10th	Night	13% 6% 2 6% 3 4 5% 4 6% 7% 43%	1900
	11th to 20th	Night	13% 5% 2 5% 3 4 4 3 4 6% 52%	2014
	21st to end	Night	18% 6% 2 6% 4 4 4 3 4 6% 41%	2090
October	1st to 10th	Night	19% 8% 2 7% 4 4 4 3 4 5% 41%	2141
	11th to 20th	Night	14% 5% 2 5% 3 3 3 3 5% 6% 50%	2280
	21st to end	Night	20% 6% 2 6% 4 3 3 3 5% 6% 42%	2695
November	1st to 10th	Night	13% 6% 2 5% 4 4 4 3 4 5% 50%	2453
	11th to 20th	Night	19% 6% 2 4 3 2 3 3 4 5% 48%	2470
	21st to end	Night	15% 5% 2 4 4 4 4 4 5% 6% 47%	2493
December	1st to 10th	Night	20% 7% 2 6% 3 4 3 3 5% 6% 39%	2660
	11th to 20th	Night	20% 7% 2 5% 4 3 3 3 5% 5% 43%	3288
	21st to end	Night	19% 9% 3 7% 4 4 4 4 5% 5% 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% 4 11% 31% 13% 2	2518
	11th to 20th	Day	45% 6% 12% 24% 12% 1	2520
	21st to end	Day	52% 8% 9% 21% 9% 1	2937
February	1st to 10th	Day	44% 6% 14% 22% 13% 1	1765
	11th to 20th	Day	41% 4 11% 25% 17% 2	1857
	21st to end	Day	47% 5% 11% 20% 13% 3	1570
March	1st to 10th	Day	48% 6% 13% 21% 10% 2	3119
	11th to 20th	Day	30% 9% 15% 31% 14% 1	3275
	21st to end	Day	44% 4 10% 17% 21% 5%	4166
April	1st to 10th	Day	43% 6% 10% 20% 16% 4	2280
	11th to 20th	Day	42% 6% 12% 21% 17% 3	2254
	21st to end	Day	42% 6% 11% 21% 17% 4	2342
May	1st to 10th	Day	52% 7% 15% 14% 11% 1	4120
	11th to 20th	Day	50% 7% 15% 18% 9% 2	4274
	21st to end	Day	34% 8% 16% 23% 17% 2	4837
June	1st to 10th	Day	40% 8% 13% 22% 15% 1	2660
	11th to 20th	Day	40% 8% 14% 24% 13% 2	2660
	21st to end	Day	37% 8% 16% 22% 16% 1	2660
July	1st to 10th	Day	43% 9% 13% 19% 15% 1	4370
	11th to 20th	Day	40% 6% 18% 22% 13% 1	4365
	21st to end	Day	46% 7% 14% 18% 14% 2	4661
August	1st to 10th	Day	46% 6% 17% 21% 9%	4170
	11th to 20th	Day	38% 6% 15% 32% 9% 1	3766
	21st to end	Day	31% 7% 14% 27% 20% 2	4180
September	1st to 10th	Day	37% 7% 14% 20% 20% 2	2280
	11th to 20th	Day	33% 5% 12% 24% 24% 2	2166
	21st to end	Day	45% 5% 11% 18% 19% 2	2090
October	1st to 10th	Day	36% 5% 11% 21% 22% 5%	3387
	11th to 20th	Day	26% 4 11% 22% 32% 5%	3140
	21st to end	Day	30% 4 15% 26% 23% 3	3113
November	1st to 10th	Day	36% 5% 14% 23% 20% 2	1698
	11th to 20th	Day	38% 5% 11% 23% 20% 3	1710
	21st to end	Day	39% 5% 15% 27% 12% 2	1684
December	1st to 10th	Day	44% 6% 16% 18% 14% 1	1520
	11th to 20th	Day	42% 4 15% 20% 17% 2	1906
	21st to end	Day	49% 8% 12% 22% 8%	2772
January	1st to 10th	Night	39% 4 11% 30% 12% 3	4429
	11th to 20th	Night	45% 4 13% 24% 13% 2	4440
	21st to end	Night	53% 5% 8% 21% 12% 1	4715
February	1st to 10th	Night	43% 6% 13% 23% 13% 2	2413
	11th to 20th	Night	44% 5% 10% 20% 16% 4	2220
	21st to end	Night	44% 4 9% 23% 16% 4	1884
March	1st to 10th	Night	52% 4 10% 21% 11% 3	3734
	11th to 20th	Night	38% 6% 13% 26% 15% 3	3680
	21st to end	Night	46% 4 8% 14% 22% 6%	3466
April	1st to 10th	Night	46% 6% 10% 18% 17% 3	1900
	11th to 20th	Night	44% 6% 10% 18% 21% 1	1875
	21st to end	Night	44% 5% 9% 21% 16% 5%	1838
May	1st to 10th	Night	56% 7% 11% 15% 10% 1	2840
	11th to 20th	Night	54% 7% 14% 14% 9% 1	2639
	21st to end	Night	42% 7% 14% 22% 14% 2	2739
June	1st to 10th	Night	43% 6% 10% 21% 19% 1	1520
	11th to 20th	Night	39% 8% 14% 27% 12% 1	1520
	21st to end	Night	40% 8% 14% 25% 13% 1	1520
July	1st to 10th	Night	49% 7% 13% 18% 12% 1	2480
	11th to 20th	Night	44% 6% 14% 25% 10% 1	2472
	21st to end	Night	49% 6% 14% 15% 14% 1	2651
August	1st to 10th	Night	51% 7% 17% 16% 9% 1	2699
	11th to 20th	Night	41% 6% 14% 29% 9% 1	3127
	21st to end	Night	30% 5% 13% 33% 18% 1	3476
September	1st to 10th	Night	39% 7% 10% 24% 18% 1	1900
	11th to 20th	Night	34% 6% 11% 24% 22% 3	2014
	21st to end	Night	44% 6% 8% 20% 19% 3	2090
October	1st to 10th	Night	40% 4 11% 23% 19% 2	3570
	11th to 20th	Night	25% 3 11% 27% 31% 4	3779
	21st to end	Night	31% 4 14% 28% 21% 3	4433
November	1st to 10th	Night	36% 5% 13% 23% 20% 4	2453
	11th to 20th	Night	40% 4 10% 23% 18% 4	2470
	21st to end	Night	37% 5% 14% 29% 13% 2	2493
December	1st to 10th	Night	46% 5% 14% 20% 13% 1	2660
	11th to 20th	Night	43% 5% 12% 19% 18% 2	3288
	21st to end	Night	47% 5% 12% 23% 12% 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	25% 22% 35% 14% 4	180
	11th to 20th	Day	23% 27% 32% 15% 3	180
	21st to end	Day	22% 20% 38% 13% 5% 1	246
February	1st to 10th	Day	28% 19% 37% 15% 2	325
	11th to 20th	Day	24% 20% 40% 14% 2	456
	21st to end	Day	29% 19% 35% 14% 4	382
March	1st to 10th	Day	23% 21% 34% 19% 3	460
	11th to 20th	Day	21% 21% 37% 16% 4 1	460
	21st to end	Day	28% 18% 34% 14% 5% 1	506
April	1st to 10th	Day	26% 20% 34% 13% 6% 1	460
	11th to 20th	Day	27% 16% 32% 19% 6% 1	452
	21st to end	Day	29% 15% 34% 16% 4 1	460
May	1st to 10th	Day	31% 17% 30% 16% 5% 1	463
	11th to 20th	Day	22% 14% 36% 21% 6% 1	487
	21st to end	Day	18% 7% 33% 26% 13% 2	529
June	1st to 10th	Day	20% 8% 31% 28% 11% 2	490
	11th to 20th	Day	16% 10% 36% 28% 10% 1	490
	21st to end	Day	14% 7% 37% 28% 12% 3	490
July	1st to 10th	Day	13% 7% 26% 34% 16% 4	485
	11th to 20th	Day	10% 5% 29% 36% 16% 4	484
	21st to end	Day	15% 9% 30% 30% 14% 2	532
August	1st to 10th	Day	15% 6% 28% 31% 16% 5%	486
	11th to 20th	Day	13% 6% 24% 36% 16% 3	479
	21st to end	Day	13% 6% 30% 32% 14% 6%	539
September	1st to 10th	Day	19% 7% 28% 24% 17% 4	490
	11th to 20th	Day	15% 7% 28% 26% 15% 10%	490
	21st to end	Day	23% 9% 29% 22% 13% 4	490
October	1st to 10th	Day	25% 8% 26% 21% 15% 4	490
	11th to 20th	Day	16% 15% 33% 23% 11% 2	490
	21st to end	Day	21% 13% 36% 18% 9% 2	439
November	1st to 10th	Day	15% 15% 30% 28% 10% 2	374
	11th to 20th	Day	22% 24% 27% 20% 6% 1	370
	21st to end	Day	19% 16% 32% 24% 8% 1	344
December	1st to 10th	Day	22% 23% 34% 16% 4 1	180
	11th to 20th	Day	34% 18% 35% 9% 4	180
	21st to end	Day	26% 17% 36% 15% 6% 1	198
January	1st to 10th	Night	20% 20% 37% 20% 3	760
	11th to 20th	Night	25% 19% 29% 24% 3	760
	21st to end	Night	21% 18% 38% 21% 2	836
February	1st to 10th	Night	21% 17% 37% 23% 2	760
	11th to 20th	Night	24% 20% 38% 16% 1	743
	21st to end	Night	25% 18% 35% 17% 4	628
March	1st to 10th	Night	23% 19% 34% 20% 5%	760
	11th to 20th	Night	21% 16% 39% 19% 4 1	760
	21st to end	Night	23% 16% 36% 20% 4	836
April	1st to 10th	Night	23% 17% 35% 20% 5%	760
	11th to 20th	Night	24% 11% 36% 25% 5%	751
	21st to end	Night	23% 12% 35% 25% 5% 1	698
May	1st to 10th	Night	24% 11% 34% 24% 7% 1	570
	11th to 20th	Night	24% 11% 33% 28% 4	465
	21st to end	Night	21% 5% 23% 35% 14% 2	411
June	1st to 10th	Night	21% 6% 25% 35% 13%	380
	11th to 20th	Night	16% 4 24% 42% 14% 1	380
	21st to end	Night	12% 4 26% 45% 11% 1	380
July	1st to 10th	Night	14% 2 23% 45% 15% 1	370
	11th to 20th	Night	13% 4 22% 41% 17% 2	368
	21st to end	Night	14% 4 23% 41% 17%	416
August	1st to 10th	Night	11% 2 25% 43% 18% 1	490
	11th to 20th	Night	15% 3 21% 36% 22% 3	750
	21st to end	Night	14% 4 19% 38% 23% 3	836
September	1st to 10th	Night	16% 4 26% 35% 16% 3	760
	11th to 20th	Night	16% 5% 20% 34% 19% 6%	760
	21st to end	Night	21% 4 26% 30% 16% 2	760
October	1st to 10th	Night	24% 7% 24% 27% 15% 3	760
	11th to 20th	Night	17% 11% 29% 30% 12% 1	760
	21st to end	Night	24% 10% 32% 24% 9%	836
November	1st to 10th	Night	14% 12% 34% 27% 11% 2	755
	11th to 20th	Night	22% 15% 33% 22% 8%	760
	21st to end	Night	18% 17% 32% 25% 7% 1	760
December	1st to 10th	Night	26% 17% 33% 19% 5% 1	760
	11th to 20th	Night	24% 17% 35% 21% 4	760
	21st to end	Night	23% 15% 37% 21% 3	836

Page generated at 2024-11-01 22:47:38. Version ac07

Copyright © 2024 Attilla Danko.