Gipe Farm
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Gipe Farm clear sky chart from 2005-11-06 to 2024-12-24.

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% 7% 3 7% 4 4 4 4 5% 7% 43%	101572
	Night	11% 7% 3 7% 4 4 4 3 5% 7% 47%	98612
Transparency	Day	39% 6% 13% 25% 16% 2	105223
	Night	37% 5% 12% 25% 18% 3	103076
Seeing	Day	14% 9% 31% 28% 15% 3	15943
	Night	14% 9% 33% 33% 11% 1	25881

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	10% 13% 5% 15% 6% 4 4 4 5% 6% 28%	2847
	11th to 20th	Day	9% 12% 5% 10% 5% 5% 7% 3 5% 8% 31%	2850
	21st to end	Day	10% 14% 6% 16% 8% 5% 4 3 4 5% 24%	3135
February	1st to 10th	Day	10% 12% 4 10% 6% 7% 4 4 5% 7% 32%	1710
	11th to 20th	Day	10% 9% 3 10% 5% 4 4 3 5% 8% 40%	1664
	21st to end	Day	11% 9% 3 8% 5% 5% 4 3 5% 6% 41%	1568
March	1st to 10th	Day	14% 9% 4 6% 3 3 3 3 3 5% 47%	3436
	11th to 20th	Day	11% 8% 2 6% 4 4 4 3 4 6% 49%	3480
	21st to end	Day	21% 11% 4 9% 5% 5% 5% 3 5% 6% 26%	3814
April	1st to 10th	Day	17% 8% 2 6% 4 3 4 2 4 6% 44%	2171
	11th to 20th	Day	16% 8% 2 6% 5% 4 4 4 6% 6% 40%	2314
	21st to end	Day	20% 7% 2 6% 4 4 4 3 5% 7% 38%	2470
May	1st to 10th	Day	15% 7% 3 7% 5% 5% 5% 5% 6% 8% 34%	4082
	11th to 20th	Day	14% 7% 3 6% 5% 4 4 3 5% 6% 42%	4082
	21st to end	Day	14% 7% 2 6% 4 4 4 3 6% 8% 41%	4693
June	1st to 10th	Day	7% 4 3 5% 5% 3 4 5% 7% 10% 47%	2660
	11th to 20th	Day	8% 5% 2 5% 4 4 5% 4 6% 9% 47%	2660
	21st to end	Day	7% 4 2 6% 6% 5% 6% 4 6% 8% 48%	2660
July	1st to 10th	Day	12% 5% 2 5% 4 4 4 5% 7% 9% 42%	4263
	11th to 20th	Day	6% 4 2 4 4 4 4 4 6% 9% 55%	4120
	21st to end	Day	4 3 1 4 4 4 4 4 7% 11% 54%	4465
August	1st to 10th	Day	6% 4 2 5% 5% 4 6% 5% 7% 10% 47%	4104
	11th to 20th	Day	12% 7% 2 6% 4 4 5% 4 6% 8% 41%	4041
	21st to end	Day	7% 4 2 7% 4 5% 5% 4 6% 8% 48%	4404
September	1st to 10th	Day	12% 4 2 4 3 2 4 3 4 7% 54%	2252
	11th to 20th	Day	10% 5% 2 4 3 4 4 2 4 7% 54%	2090
	21st to end	Day	11% 5% 2 4 3 4 3 3 5% 6% 56%	2090
October	1st to 10th	Day	14% 5% 1 5% 2 2 3 2 5% 7% 52%	1918
	11th to 20th	Day	13% 7% 2 4 2 3 3 3 3 5% 56%	1900
	21st to end	Day	13% 7% 3 5% 4 4 4 3 5% 6% 47%	2090
November	1st to 10th	Day	12% 4 2 4 3 3 3 4 5% 6% 53%	1830
	11th to 20th	Day	11% 8% 2 7% 4 3 3 3 5% 6% 47%	1690
	21st to end	Day	13% 8% 4 6% 4 3 4 3 5% 8% 42%	1600
December	1st to 10th	Day	9% 7% 3 9% 5% 4 4 4 5% 7% 44%	1600
	11th to 20th	Day	9% 10% 3 9% 6% 4 5% 4 6% 7% 37%	1998
	21st to end	Day	17% 11% 6% 15% 5% 4 5% 4 4 5% 24%	2821
January	1st to 10th	Night	9% 10% 4 20% 7% 5% 4 3 5% 6% 28%	4108
	11th to 20th	Night	9% 11% 3 9% 4 5% 7% 4 8% 6% 34%	4120
	21st to end	Night	13% 14% 5% 13% 5% 4 4 3 4 5% 30%	4532
February	1st to 10th	Night	12% 11% 4 8% 5% 5% 4 4 4 6% 37%	2470
	11th to 20th	Night	10% 9% 3 6% 4 4 4 3 6% 7% 43%	2403
	21st to end	Night	10% 8% 3 7% 4 4 3 3 4 5% 48%	1901
March	1st to 10th	Night	12% 7% 2 5% 3 3 3 3 4 5% 52%	3419
	11th to 20th	Night	12% 7% 2 5% 2 2 3 2 4 6% 56%	3480
	21st to end	Night	19% 9% 3 9% 4 4 4 4 6% 6% 32%	3817
April	1st to 10th	Night	13% 8% 2 5% 4 4 3 4 4 6% 48%	2007
	11th to 20th	Night	12% 8% 2 6% 4 4 4 4 5% 6% 46%	1813
	21st to end	Night	16% 9% 2 6% 3 4 3 3 4 6% 44%	1710
May	1st to 10th	Night	19% 7% 2 5% 4 3 3 3 4 5% 44%	2823
	11th to 20th	Night	13% 6% 2 5% 3 4 3 3 5% 6% 49%	2823
	21st to end	Night	16% 6% 2 5% 4 4 3 3 5% 6% 46%	2869
June	1st to 10th	Night	5% 4 2 4 3 4 5% 5% 6% 10% 53%	1520
	11th to 20th	Night	7% 4 1 4 3 3 4 3 8% 11% 52%	1520
	21st to end	Night	5% 3 2 4 4 4 4 4 6% 8% 55%	1520
July	1st to 10th	Night	8% 5% 2 7% 4 4 4 4 5% 7% 51%	2688
	11th to 20th	Night	4 2 1 3 3 3 3 3 5% 8% 64%	2850
	21st to end	Night	4 2 1 3 4 4 4 4 6% 11% 56%	3098
August	1st to 10th	Night	4 3 1 5% 3 3 3 3 6% 10% 60%	2836
	11th to 20th	Night	11% 5% 2 5% 3 4 3 3 5% 7% 51%	2798
	21st to end	Night	7% 4 1 4 3 3 4 3 6% 8% 57%	3259
September	1st to 10th	Night	9% 4 2 4 3 4 3 2 4 5% 59%	1924
	11th to 20th	Night	9% 5% 1 4 3 2 4 3 4 7% 57%	2090
	21st to end	Night	9% 4 1 4 3 3 3 3 4 5% 61%	2090
October	1st to 10th	Night	12% 6% 2 4 2 2 3 3 4 7% 54%	2242
	11th to 20th	Night	13% 6% 2 4 3 3 3 3 4 5% 55%	2280
	21st to end	Night	14% 6% 2 4 3 3 4 3 4 6% 51%	2508
November	1st to 10th	Night	9% 4 2 4 3 3 3 3 6% 7% 55%	2464
	11th to 20th	Night	11% 6% 2 5% 3 3 4 3 5% 6% 51%	2709
	21st to end	Night	12% 8% 3 5% 3 3 3 3 4 6% 50%	2800
December	1st to 10th	Night	9% 8% 3 7% 5% 4 4 3 6% 7% 45%	2800
	11th to 20th	Night	10% 9% 4 7% 4 3 3 3 5% 6% 46%	3419
	21st to end	Night	18% 13% 8% 12% 3 3 3 3 3 4 29%	4902

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	57% 6% 13% 16% 7% 1	2848
	11th to 20th	Day	53% 4 14% 21% 8%	2850
	21st to end	Day	62% 5% 12% 14% 6%	3135
February	1st to 10th	Day	52% 6% 13% 18% 10% 1	1710
	11th to 20th	Day	44% 4 12% 23% 13% 3	1673
	21st to end	Day	44% 4 13% 22% 13% 3	1568
March	1st to 10th	Day	41% 4 9% 23% 19% 3	3436
	11th to 20th	Day	37% 6% 11% 27% 18% 2	3480
	21st to end	Day	58% 7% 18% 12% 4 1	3814
April	1st to 10th	Day	43% 5% 11% 27% 12% 2	2171
	11th to 20th	Day	44% 5% 13% 22% 13% 2	2314
	21st to end	Day	47% 6% 11% 23% 13% 1	2470
May	1st to 10th	Day	44% 9% 14% 20% 12% 2	4120
	11th to 20th	Day	42% 7% 10% 25% 15% 1	4086
	21st to end	Day	39% 7% 13% 24% 16% 1	4706
June	1st to 10th	Day	31% 8% 17% 27% 14% 3	2660
	11th to 20th	Day	33% 7% 13% 28% 17% 1	2660
	21st to end	Day	33% 8% 14% 28% 14% 4	2660
July	1st to 10th	Day	36% 7% 15% 28% 12% 2	4199
	11th to 20th	Day	26% 7% 13% 32% 20% 3	4051
	21st to end	Day	22% 9% 17% 32% 18% 2	4325
August	1st to 10th	Day	30% 7% 14% 30% 18% 1	4090
	11th to 20th	Day	39% 6% 14% 25% 15% 1	4080
	21st to end	Day	33% 7% 14% 26% 15% 5%	4403
September	1st to 10th	Day	30% 6% 11% 28% 20% 5%	2252
	11th to 20th	Day	31% 6% 10% 33% 19% 1	2090
	21st to end	Day	30% 4 10% 31% 24% 1	2090
October	1st to 10th	Day	20% 3 7% 20% 47% 3	3178
	11th to 20th	Day	20% 3 11% 31% 28% 7%	3140
	21st to end	Day	35% 4 8% 28% 22% 3	3428
November	1st to 10th	Day	32% 5% 13% 28% 20% 2	1830
	11th to 20th	Day	39% 4 13% 24% 18% 1	1690
	21st to end	Day	42% 5% 12% 28% 13% 1	1600
December	1st to 10th	Day	39% 6% 16% 25% 13% 1	1600
	11th to 20th	Day	47% 6% 17% 25% 6%	1995
	21st to end	Day	63% 5% 9% 16% 6%	2821
January	1st to 10th	Night	57% 5% 12% 16% 10%	4108
	11th to 20th	Night	48% 5% 14% 22% 10% 1	4120
	21st to end	Night	56% 5% 15% 15% 8% 1	4532
February	1st to 10th	Night	48% 5% 13% 19% 12% 3	2470
	11th to 20th	Night	40% 5% 13% 25% 15% 2	2404
	21st to end	Night	39% 4 10% 22% 21% 4	1901
March	1st to 10th	Night	34% 4 9% 27% 22% 3	3419
	11th to 20th	Night	32% 4 8% 32% 18% 6%	3480
	21st to end	Night	51% 8% 20% 15% 5% 1	3817
April	1st to 10th	Night	38% 4 11% 27% 17% 3	2007
	11th to 20th	Night	39% 5% 10% 26% 17% 3	1813
	21st to end	Night	42% 5% 11% 24% 16% 2	1710
May	1st to 10th	Night	41% 6% 12% 21% 18% 2	2850
	11th to 20th	Night	35% 7% 11% 25% 20% 2	2824
	21st to end	Night	39% 7% 13% 20% 19% 3	2877
June	1st to 10th	Night	25% 7% 16% 31% 17% 4	1520
	11th to 20th	Night	25% 8% 15% 28% 21% 4	1520
	21st to end	Night	24% 7% 15% 31% 19% 3	1520
July	1st to 10th	Night	32% 6% 13% 28% 17% 3	2644
	11th to 20th	Night	19% 6% 14% 35% 23% 3	2796
	21st to end	Night	20% 8% 16% 34% 20% 2	2999
August	1st to 10th	Night	22% 5% 15% 35% 21% 2	2826
	11th to 20th	Night	33% 6% 13% 27% 20% 2	2825
	21st to end	Night	25% 6% 17% 27% 17% 8%	3259
September	1st to 10th	Night	28% 5% 11% 27% 23% 7%	1924
	11th to 20th	Night	27% 5% 12% 33% 20% 3	2090
	21st to end	Night	27% 3 9% 29% 28% 3	2090
October	1st to 10th	Night	20% 3 6% 19% 49% 3	3736
	11th to 20th	Night	23% 3 7% 29% 29% 9%	3779
	21st to end	Night	35% 4 9% 28% 22% 2	4120
November	1st to 10th	Night	28% 5% 16% 24% 23% 4	2464
	11th to 20th	Night	33% 5% 11% 30% 19% 3	2709
	21st to end	Night	37% 4 12% 28% 17% 2	2800
December	1st to 10th	Night	39% 5% 12% 31% 12% 1	2800
	11th to 20th	Night	39% 5% 14% 32% 9%	3421
	21st to end	Night	59% 5% 10% 18% 7% 1	4902

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	21% 14% 32% 24% 7% 1	270
	11th to 20th	Day	20% 14% 37% 21% 6% 1	270
	21st to end	Day	14% 10% 45% 25% 5%	297
February	1st to 10th	Day	19% 15% 45% 17% 4	270
	11th to 20th	Day	17% 16% 40% 20% 6% 1	270
	21st to end	Day	15% 15% 47% 19% 4	225
March	1st to 10th	Day	19% 14% 43% 18% 4 1	270
	11th to 20th	Day	28% 12% 35% 19% 6% 1	270
	21st to end	Day	29% 19% 36% 13% 3 1	297
April	1st to 10th	Day	25% 17% 38% 17% 4	351
	11th to 20th	Day	21% 15% 36% 21% 7%	512
	21st to end	Day	21% 15% 34% 22% 7% 1	650
May	1st to 10th	Day	19% 14% 34% 23% 9% 1	653
	11th to 20th	Day	18% 9% 33% 27% 11% 3	675
	21st to end	Day	19% 6% 30% 28% 15% 2	734
June	1st to 10th	Day	7% 6% 24% 34% 24% 6%	680
	11th to 20th	Day	9% 6% 30% 34% 18% 4	680
	21st to end	Day	7% 6% 36% 31% 16% 3	680
July	1st to 10th	Day	9% 4 16% 34% 28% 10%	671
	11th to 20th	Day	6% 2 24% 38% 24% 6%	668
	21st to end	Day	6% 2 18% 42% 26% 5%	739
August	1st to 10th	Day	8% 3 20% 39% 26% 5%	676
	11th to 20th	Day	11% 4 18% 39% 24% 4	665
	21st to end	Day	10% 3 21% 36% 24% 6%	672
September	1st to 10th	Day	12% 4 27% 31% 21% 5%	462
	11th to 20th	Day	6% 4 32% 32% 19% 6%	300
	21st to end	Day	14% 8% 31% 26% 19% 1	300
October	1st to 10th	Day	21% 7% 24% 28% 14% 6%	300
	11th to 20th	Day	10% 17% 43% 22% 7% 1	300
	21st to end	Day	18% 16% 37% 20% 7% 2	330
November	1st to 10th	Day	16% 12% 40% 21% 9% 2	300
	11th to 20th	Day	19% 15% 38% 20% 8%	300
	21st to end	Day	23% 12% 36% 20% 8% 1	300
December	1st to 10th	Day	8% 17% 38% 29% 7% 2	300
	11th to 20th	Day	16% 16% 35% 24% 8%	300
	21st to end	Day	21% 13% 44% 20% 2	306
January	1st to 10th	Night	12% 13% 36% 32% 7%	950
	11th to 20th	Night	15% 13% 36% 29% 7% 1	950
	21st to end	Night	18% 10% 37% 30% 6%	1045
February	1st to 10th	Night	16% 11% 37% 31% 4	950
	11th to 20th	Night	14% 12% 41% 28% 5%	929
	21st to end	Night	14% 13% 45% 23% 5% 1	645
March	1st to 10th	Night	14% 14% 39% 26% 7% 1	570
	11th to 20th	Night	20% 9% 37% 28% 6% 1	570
	21st to end	Night	23% 13% 37% 21% 6%	627
April	1st to 10th	Night	16% 16% 40% 24% 5%	570
	11th to 20th	Night	17% 13% 40% 25% 4 1	563
	21st to end	Night	19% 9% 38% 26% 8%	570
May	1st to 10th	Night	17% 9% 34% 32% 8% 1	570
	11th to 20th	Night	16% 7% 31% 36% 9% 1	561
	21st to end	Night	15% 6% 31% 33% 14%	617
June	1st to 10th	Night	6% 4 27% 43% 19%	570
	11th to 20th	Night	7% 3 32% 42% 15%	570
	21st to end	Night	5% 4 33% 43% 14%	570
July	1st to 10th	Night	7% 2 17% 42% 30% 2	555
	11th to 20th	Night	4 2 18% 50% 24% 2	552
	21st to end	Night	4 1 16% 52% 25% 1	624
August	1st to 10th	Night	6% 2 19% 49% 23% 2	567
	11th to 20th	Night	9% 3 16% 47% 23% 1	564
	21st to end	Night	7% 2 21% 41% 26% 2	627
September	1st to 10th	Night	9% 4 25% 36% 24% 2	570
	11th to 20th	Night	11% 3 29% 37% 19% 2	570
	21st to end	Night	11% 6% 31% 36% 16% 1	570
October	1st to 10th	Night	15% 6% 31% 33% 12% 2	722
	11th to 20th	Night	16% 9% 37% 30% 8%	760
	21st to end	Night	18% 12% 33% 29% 8%	836
November	1st to 10th	Night	12% 12% 33% 35% 9%	904
	11th to 20th	Night	14% 13% 39% 28% 6%	1000
	21st to end	Night	16% 11% 36% 29% 8%	1000
December	1st to 10th	Night	14% 12% 37% 31% 6%	1000
	11th to 20th	Night	17% 9% 36% 31% 6% 1	1000
	21st to end	Night	19% 13% 36% 28% 4	1063

Page generated at 2024-12-21 03:13:53. Version ac07

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