Mole Hill Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mole Hill Observatory clear sky chart from 2005-11-06 to 2024-11-05.

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	11% 6% 2 6% 5% 5% 5% 4 7% 9% 40%	100933
	Night	12% 6% 2 5% 4 4 4 3 6% 8% 45%	98205
Transparency	Day	20% 49% 9% 12% 7% 3	104687
	Night	20% 48% 8% 12% 8% 4	102565
Seeing	Day	11% 3 12% 26% 34% 15%	14631
	Night	14% 4 15% 30% 30% 7%	24529

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	18% 11% 3 6% 4 4 5% 4 5% 6% 36%	2847
	11th to 20th	Day	15% 7% 2 3 3 3 3 4 6% 8% 46%	2850
	21st to end	Day	24% 7% 2 6% 4 3 4 4 7% 6% 34%	3240
February	1st to 10th	Day	19% 10% 3 7% 4 3 2 3 4 6% 39%	1900
	11th to 20th	Day	18% 9% 3 6% 4 3 3 4 4 5% 40%	1849
	21st to end	Day	19% 7% 2 6% 3 2 3 4 5% 7% 41%	1676
March	1st to 10th	Day	19% 8% 3 7% 5% 5% 5% 4 6% 8% 30%	3436
	11th to 20th	Day	18% 10% 4 9% 6% 5% 6% 4 5% 6% 27%	3480
	21st to end	Day	12% 5% 2 6% 4 4 4 4 5% 7% 48%	3814
April	1st to 10th	Day	12% 8% 3 6% 4 4 5% 4 6% 9% 40%	2090
	11th to 20th	Day	15% 8% 3 6% 6% 5% 5% 4 5% 7% 37%	2098
	21st to end	Day	11% 7% 2 6% 5% 4 4 4 5% 8% 44%	2280
May	1st to 10th	Day	16% 7% 3 8% 6% 6% 6% 5% 6% 7% 30%	3974
	11th to 20th	Day	12% 6% 3 7% 5% 4 5% 5% 7% 8% 39%	4082
	21st to end	Day	5% 5% 2 6% 5% 6% 7% 6% 10% 13% 37%	4477
June	1st to 10th	Day	4 3 2 4 4 4 5% 5% 10% 13% 45%	2470
	11th to 20th	Day	5% 4 2 5% 5% 6% 6% 5% 9% 12% 41%	2470
	21st to end	Day	7% 5% 2 6% 6% 6% 6% 6% 10% 12% 33%	2470
July	1st to 10th	Day	8% 5% 2 5% 4 5% 5% 5% 8% 11% 41%	4120
	11th to 20th	Day	6% 6% 3 9% 7% 7% 7% 6% 9% 12% 28%	4120
	21st to end	Day	10% 7% 3 6% 5% 5% 6% 4 9% 12% 32%	4465
August	1st to 10th	Day	1 2 1 2 3 3 4 3 6% 10% 65%	4104
	11th to 20th	Day	3 2 1 3 3 4 5% 5% 10% 15% 48%	3860
	21st to end	Day	5% 4 2 7% 5% 6% 7% 5% 9% 12% 38%	3828
September	1st to 10th	Day	8% 7% 3 8% 5% 7% 6% 5% 9% 11% 31%	2090
	11th to 20th	Day	11% 6% 2 6% 6% 5% 5% 4 8% 9% 37%	2090
	21st to end	Day	8% 6% 2 5% 4 5% 6% 5% 7% 9% 44%	2090
October	1st to 10th	Day	5% 4 1 4 4 4 5% 4 7% 10% 51%	2068
	11th to 20th	Day	9% 5% 2 6% 4 4 4 4 5% 7% 50%	1900
	21st to end	Day	10% 5% 2 6% 3 4 4 3 5% 7% 52%	2090
November	1st to 10th	Day	9% 6% 3 6% 5% 4 5% 5% 7% 9% 41%	1898
	11th to 20th	Day	14% 5% 2 6% 4 4 4 4 4 6% 46%	1900
	21st to end	Day	17% 8% 2 6% 5% 5% 5% 3 4 6% 39%	1801
December	1st to 10th	Day	18% 8% 3 6% 4 4 4 3 5% 7% 39%	1710
	11th to 20th	Day	13% 9% 3 8% 5% 4 4 4 5% 7% 39%	2161
	21st to end	Day	16% 6% 3 6% 4 4 4 3 5% 7% 42%	3135
January	1st to 10th	Night	20% 10% 3 7% 4 3 3 3 4 5% 38%	4108
	11th to 20th	Night	14% 6% 2 5% 3 2 3 3 6% 7% 50%	4120
	21st to end	Night	23% 8% 3 6% 4 3 4 3 6% 6% 35%	4454
February	1st to 10th	Night	18% 9% 3 6% 4 3 4 3 4 6% 40%	2280
	11th to 20th	Night	18% 7% 2 4 3 3 3 4 5% 7% 44%	2218
	21st to end	Night	18% 9% 2 5% 5% 3 4 3 5% 5% 40%	1775
March	1st to 10th	Night	23% 10% 3 6% 3 3 4 3 6% 7% 32%	3419
	11th to 20th	Night	20% 10% 3 9% 5% 6% 5% 3 5% 6% 28%	3480
	21st to end	Night	12% 6% 2 5% 3 4 3 3 5% 6% 52%	3817
April	1st to 10th	Night	14% 8% 3 6% 4 4 5% 3 6% 8% 38%	2090
	11th to 20th	Night	17% 7% 3 5% 4 3 3 3 4 7% 42%	2028
	21st to end	Night	14% 6% 2 6% 4 4 5% 4 6% 7% 41%	1900
May	1st to 10th	Night	24% 8% 2 5% 3 4 3 3 6% 7% 34%	2923
	11th to 20th	Night	14% 7% 2 6% 4 4 4 4 5% 8% 42%	2823
	21st to end	Night	11% 7% 2 6% 4 4 4 4 7% 12% 39%	3090
June	1st to 10th	Night	5% 3 1 4 3 3 4 4 8% 11% 54%	1710
	11th to 20th	Night	5% 4 1 4 3 5% 5% 4 6% 12% 50%	1710
	21st to end	Night	5% 5% 2 5% 4 4 5% 6% 9% 13% 42%	1710
July	1st to 10th	Night	6% 4 2 5% 3 4 4 4 6% 11% 51%	2850
	11th to 20th	Night	3 5% 3 6% 6% 5% 6% 6% 8% 13% 39%	2850
	21st to end	Night	7% 5% 2 6% 5% 5% 5% 4 8% 12% 40%	3098
August	1st to 10th	Night	1 1 2 1 2 2 2 4 8% 77%	2836
	11th to 20th	Night	2 2 1 3 3 3 4 4 7% 14% 58%	2967
	21st to end	Night	3 2 1 3 3 3 4 4 8% 13% 56%	3828
September	1st to 10th	Night	7% 4 3 6% 4 5% 5% 4 9% 12% 42%	2090
	11th to 20th	Night	9% 6% 2 7% 4 3 4 4 7% 9% 45%	2090
	21st to end	Night	6% 4 2 5% 4 4 4 4 6% 9% 52%	2090
October	1st to 10th	Night	4 3 2 5% 4 4 4 3 6% 8% 56%	2090
	11th to 20th	Night	9% 4 2 5% 2 3 3 2 4 7% 60%	2280
	21st to end	Night	8% 3 2 4 3 3 3 3 3 6% 61%	2508
November	1st to 10th	Night	9% 5% 2 5% 4 4 4 3 5% 7% 54%	2280
	11th to 20th	Night	14% 6% 2 6% 3 4 3 3 4 5% 48%	2280
	21st to end	Night	15% 6% 2 6% 4 5% 5% 3 5% 7% 43%	2375
December	1st to 10th	Night	18% 6% 2 6% 4 3 3 3 5% 6% 43%	2470
	11th to 20th	Night	15% 8% 2 7% 4 4 6% 4 6% 7% 37%	3036
	21st to end	Night	14% 7% 3 8% 4 4 4 3 5% 6% 42%	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	34% 38% 4 9% 8% 6%	2848
	11th to 20th	Day	19% 43% 8% 13% 10% 6%	2850
	21st to end	Day	31% 40% 4 10% 12% 3	3240
February	1st to 10th	Day	20% 65% 2 3 4 5%	1900
	11th to 20th	Day	15% 64% 4 9% 5% 2	1859
	21st to end	Day	17% 66% 4 5% 4 3	1676
March	1st to 10th	Day	38% 45% 7% 8% 2	3436
	11th to 20th	Day	40% 44% 5% 6% 4 1	3480
	21st to end	Day	19% 42% 8% 14% 12% 5%	3814
April	1st to 10th	Day	15% 66% 3 5% 7% 5%	2090
	11th to 20th	Day	16% 67% 4 6% 4 3	2098
	21st to end	Day	13% 66% 3 10% 6% 2	2280
May	1st to 10th	Day	33% 44% 9% 8% 4 2	4010
	11th to 20th	Day	26% 42% 8% 11% 10% 3	4086
	21st to end	Day	20% 46% 10% 23% 2	4489
June	1st to 10th	Day	8% 67% 8% 13% 5%	2470
	11th to 20th	Day	12% 68% 5% 10% 5%	2470
	21st to end	Day	12% 66% 9% 11% 2	2470
July	1st to 10th	Day	16% 40% 25% 18% 1	4056
	11th to 20th	Day	31% 42% 16% 8% 3	4051
	21st to end	Day	28% 39% 17% 14% 1	4325
August	1st to 10th	Day	5% 38% 12% 37% 9%	4090
	11th to 20th	Day	10% 41% 29% 19% 1	3899
	21st to end	Day	19% 42% 15% 18% 4 1	3827
September	1st to 10th	Day	14% 63% 8% 7% 6% 1	2090
	11th to 20th	Day	12% 62% 7% 12% 6% 1	2090
	21st to end	Day	14% 62% 8% 10% 3 2	2090
October	1st to 10th	Day	11% 38% 4 9% 16% 22%	3432
	11th to 20th	Day	12% 39% 7% 13% 21% 7%	3140
	21st to end	Day	17% 39% 5% 16% 20% 3	3428
November	1st to 10th	Day	21% 60% 8% 6% 3 2	1898
	11th to 20th	Day	21% 60% 4 7% 4 4	1900
	21st to end	Day	21% 60% 4 7% 7% 1	1801
December	1st to 10th	Day	20% 60% 3 6% 8% 2	1710
	11th to 20th	Day	20% 50% 3 7% 12% 7%	2159
	21st to end	Day	29% 39% 4 12% 9% 8%	3135
January	1st to 10th	Night	36% 38% 5% 6% 6% 10%	4108
	11th to 20th	Night	21% 39% 5% 13% 15% 7%	4120
	21st to end	Night	30% 40% 4 8% 13% 5%	4454
February	1st to 10th	Night	19% 65% 3 3 5% 5%	2280
	11th to 20th	Night	13% 64% 3 9% 6% 4	2218
	21st to end	Night	17% 65% 3 6% 5% 3	1775
March	1st to 10th	Night	37% 43% 8% 9% 4	3419
	11th to 20th	Night	41% 42% 6% 6% 3 1	3480
	21st to end	Night	18% 41% 8% 12% 18% 5%	3817
April	1st to 10th	Night	15% 65% 3 6% 6% 4	2090
	11th to 20th	Night	16% 66% 5% 5% 4 4	2028
	21st to end	Night	14% 65% 5% 9% 5% 2	1900
May	1st to 10th	Night	33% 42% 8% 9% 4 3	2952
	11th to 20th	Night	26% 42% 9% 12% 7% 4	2824
	21st to end	Night	22% 43% 11% 21% 3	3099
June	1st to 10th	Night	8% 66% 6% 14% 6%	1710
	11th to 20th	Night	14% 66% 4 10% 6%	1710
	21st to end	Night	13% 65% 7% 13% 1	1710
July	1st to 10th	Night	13% 38% 23% 24% 2	2805
	11th to 20th	Night	25% 42% 18% 13% 2	2796
	21st to end	Night	26% 38% 20% 14% 2	2999
August	1st to 10th	Night	3 37% 8% 42% 10%	2826
	11th to 20th	Night	8% 39% 28% 24% 1	2994
	21st to end	Night	10% 42% 19% 22% 6%	3828
September	1st to 10th	Night	11% 62% 11% 8% 6% 2	2090
	11th to 20th	Night	13% 61% 6% 12% 7% 1	2090
	21st to end	Night	14% 62% 6% 12% 3 2	2090
October	1st to 10th	Night	11% 38% 5% 8% 11% 26%	3480
	11th to 20th	Night	9% 37% 7% 14% 23% 10%	3779
	21st to end	Night	12% 38% 4 17% 24% 6%	4120
November	1st to 10th	Night	18% 60% 7% 8% 5% 3	2280
	11th to 20th	Night	22% 60% 4 7% 4 3	2280
	21st to end	Night	20% 61% 3 7% 7% 2	2375
December	1st to 10th	Night	18% 60% 4 7% 8% 3	2470
	11th to 20th	Night	21% 50% 4 7% 8% 10%	3037
	21st to end	Night	30% 39% 4 9% 12% 5%	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	19% 6% 22% 38% 15%	270
	11th to 20th	Day	21% 9% 23% 30% 17% 1	270
	21st to end	Day	18% 6% 30% 30% 15%	297
February	1st to 10th	Day	26% 9% 20% 29% 15% 1	270
	11th to 20th	Day	24% 7% 20% 33% 15% 1	270
	21st to end	Day	18% 8% 25% 40% 8%	225
March	1st to 10th	Day	21% 6% 21% 38% 13% 1	270
	11th to 20th	Day	21% 6% 25% 37% 11% 1	270
	21st to end	Day	13% 5% 27% 44% 12%	297
April	1st to 10th	Day	17% 5% 28% 35% 14%	270
	11th to 20th	Day	13% 8% 28% 33% 16% 2	296
	21st to end	Day	13% 5% 21% 43% 18% 1	460
May	1st to 10th	Day	12% 7% 19% 45% 16% 1	582
	11th to 20th	Day	12% 3 14% 42% 26% 3	675
	21st to end	Day	7% 2 12% 40% 36% 4	734
June	1st to 10th	Day	4 1 7% 29% 48% 11%	680
	11th to 20th	Day	7% 1 4 30% 47% 12%	680
	21st to end	Day	7% 1 6% 17% 50% 19%	680
July	1st to 10th	Day	8% 1 3 13% 46% 28%	671
	11th to 20th	Day	4 2 6% 57% 30%	668
	21st to end	Day	6% 1 2 9% 51% 32%	739
August	1st to 10th	Day	1 1 8% 52% 38%	676
	11th to 20th	Day	3 2 6% 48% 42%	562
	21st to end	Day	9% 1 2 8% 34% 45%	330
September	1st to 10th	Day	9% 1 4 12% 43% 31%	300
	11th to 20th	Day	9% 1 3 13% 39% 37%	300
	21st to end	Day	6% 3 14% 47% 31%	300
October	1st to 10th	Day	6% 1 6% 20% 48% 19%	300
	11th to 20th	Day	9% 2 9% 24% 38% 18%	300
	21st to end	Day	15% 5% 16% 23% 35% 7%	330
November	1st to 10th	Day	16% 2 7% 24% 40% 10%	282
	11th to 20th	Day	20% 3 13% 30% 29% 6%	270
	21st to end	Day	23% 5% 21% 31% 14% 6%	270
December	1st to 10th	Day	21% 4 15% 30% 25% 5%	270
	11th to 20th	Day	20% 6% 25% 31% 17% 1	270
	21st to end	Day	20% 5% 17% 37% 18% 2	297
January	1st to 10th	Night	21% 7% 24% 32% 16% 1	950
	11th to 20th	Night	20% 7% 22% 37% 13% 1	950
	21st to end	Night	21% 7% 26% 34% 13%	993
February	1st to 10th	Night	24% 7% 23% 34% 11%	760
	11th to 20th	Night	23% 9% 19% 35% 14%	744
	21st to end	Night	21% 8% 25% 36% 9%	519
March	1st to 10th	Night	19% 6% 24% 35% 15%	570
	11th to 20th	Night	16% 7% 21% 43% 13%	570
	21st to end	Night	15% 6% 22% 41% 15% 1	627
April	1st to 10th	Night	16% 5% 24% 43% 12%	570
	11th to 20th	Night	19% 6% 22% 37% 16%	563
	21st to end	Night	16% 6% 22% 39% 16% 1	570
May	1st to 10th	Night	15% 4 20% 47% 14%	570
	11th to 20th	Night	11% 3 14% 48% 22% 2	561
	21st to end	Night	6% 2 12% 40% 37% 2	617
June	1st to 10th	Night	5% 1 5% 29% 54% 5%	570
	11th to 20th	Night	5% 1 3 33% 53% 4	570
	21st to end	Night	7% 1 6% 21% 50% 15%	570
July	1st to 10th	Night	6% 2 3 16% 53% 20%	555
	11th to 20th	Night	2 1 3 10% 57% 28%	552
	21st to end	Night	4 1 1 13% 59% 22%	624
August	1st to 10th	Night	1 1 8% 62% 28%	567
	11th to 20th	Night	3 1 6% 65% 25%	564
	21st to end	Night	5% 1 11% 51% 32%	627
September	1st to 10th	Night	9% 1 3 12% 53% 22%	570
	11th to 20th	Night	11% 1 4 14% 49% 20%	570
	21st to end	Night	7% 2 5% 19% 52% 14%	570
October	1st to 10th	Night	5% 1 5% 22% 52% 15%	570
	11th to 20th	Night	11% 2 8% 31% 41% 6%	760
	21st to end	Night	10% 3 15% 35% 33% 6%	836
November	1st to 10th	Night	11% 3 9% 31% 38% 7%	760
	11th to 20th	Night	17% 4 17% 30% 30% 3	760
	21st to end	Night	18% 5% 21% 34% 19% 3	855
December	1st to 10th	Night	21% 5% 19% 28% 24% 3	950
	11th to 20th	Night	20% 8% 21% 32% 17% 1	950
	21st to end	Night	22% 8% 22% 32% 15% 1	1045

Page generated at 2024-11-03 01:11:15. Version ac07

Copyright © 2024 Attilla Danko.