RabbitEye Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the RabbitEye Observatory clear sky chart from 2005-11-06 to 2026-04-17.

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	10% 6% 2 7% 5% 5% 5% 4 7% 9% 40%	131688
	Night	10% 6% 2 6% 4 4 5% 4 6% 8% 44%	130481
Transparency	Day	38% 9% 13% 17% 16% 7%	135386
	Night	36% 8% 13% 17% 18% 9%	134853
Seeing	Day	13% 10% 25% 25% 18% 9%	17257
	Night	12% 8% 25% 32% 20% 3	27385

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	8% 5% 2 6% 4 4 4 3 5% 8% 51%	5258
	11th to 20th	Day	15% 6% 2 5% 3 3 4 4 5% 7% 47%	5280
	21st to end	Day	11% 7% 3 7% 4 4 4 3 5% 7% 45%	5780
February	1st to 10th	Day	14% 7% 2 6% 5% 4 4 4 4 7% 42%	2053
	11th to 20th	Day	16% 6% 2 5% 4 3 4 3 4 5% 48%	2048
	21st to end	Day	13% 7% 3 6% 4 3 4 3 5% 6% 47%	1776
March	1st to 10th	Day	17% 8% 3 6% 4 4 4 3 5% 7% 39%	5045
	11th to 20th	Day	7% 4 1 5% 4 4 4 3 5% 7% 55%	5090
	21st to end	Day	14% 6% 2 6% 4 4 4 3 5% 5% 48%	5586
April	1st to 10th	Day	9% 6% 2 5% 5% 5% 4 4 6% 7% 48%	2310
	11th to 20th	Day	11% 5% 2 6% 4 3 4 3 5% 7% 49%	2325
	21st to end	Day	6% 4 2 4 4 4 4 4 6% 8% 53%	2516
May	1st to 10th	Day	8% 6% 2 8% 6% 5% 6% 4 7% 8% 39%	5862
	11th to 20th	Day	13% 6% 2 6% 4 5% 5% 4 6% 9% 40%	5861
	21st to end	Day	6% 3 1 6% 5% 5% 6% 5% 8% 10% 44%	6433
June	1st to 10th	Day	10% 7% 3 9% 7% 7% 7% 5% 7% 10% 30%	2600
	11th to 20th	Day	6% 5% 2 7% 6% 7% 7% 7% 10% 12% 33%	2600
	21st to end	Day	7% 5% 3 8% 7% 7% 8% 6% 10% 11% 28%	2600
July	1st to 10th	Day	8% 8% 4 11% 9% 9% 9% 7% 10% 10% 16%	5900
	11th to 20th	Day	3 4 2 7% 7% 7% 9% 8% 11% 15% 28%	5900
	21st to end	Day	5% 5% 2 8% 8% 8% 8% 7% 10% 13% 27%	6424
August	1st to 10th	Day	17% 7% 3 9% 6% 7% 7% 5% 8% 10% 21%	4234
	11th to 20th	Day	5% 5% 2 7% 6% 7% 7% 6% 9% 13% 32%	4174
	21st to end	Day	10% 6% 3 8% 7% 8% 8% 6% 9% 11% 25%	4064
September	1st to 10th	Day	12% 7% 3 9% 7% 7% 7% 5% 8% 8% 29%	2200
	11th to 20th	Day	11% 8% 2 8% 7% 5% 6% 5% 7% 9% 32%	2200
	21st to end	Day	12% 7% 3 8% 5% 6% 5% 4 6% 7% 37%	2200
October	1st to 10th	Day	14% 6% 3 6% 5% 5% 5% 4 5% 7% 42%	2156
	11th to 20th	Day	9% 5% 2 5% 3 3 3 3 5% 7% 57%	2000
	21st to end	Day	9% 5% 2 5% 4 4 4 3 5% 6% 54%	2200
November	1st to 10th	Day	11% 4 2 5% 5% 3 4 3 5% 7% 51%	2057
	11th to 20th	Day	12% 6% 2 5% 3 3 3 3 4 5% 55%	2018
	21st to end	Day	11% 6% 2 6% 4 4 4 3 5% 7% 48%	1890
December	1st to 10th	Day	8% 6% 2 7% 4 4 3 3 4 6% 52%	3020
	11th to 20th	Day	14% 7% 2 6% 3 3 3 3 5% 7% 47%	3463
	21st to end	Day	15% 9% 3 7% 4 4 4 3 5% 6% 41%	4565
January	1st to 10th	Night	9% 6% 2 5% 3 4 4 3 5% 7% 51%	7635
	11th to 20th	Night	11% 6% 2 6% 4 4 4 4 5% 8% 46%	7680
	21st to end	Night	15% 8% 3 6% 3 4 3 3 4 7% 45%	8401
February	1st to 10th	Night	13% 7% 3 6% 4 4 4 4 5% 6% 45%	2562
	11th to 20th	Night	15% 8% 2 5% 3 5% 3 3 4 5% 45%	2458
	21st to end	Night	12% 6% 2 6% 4 4 5% 4 5% 6% 47%	2029
March	1st to 10th	Night	19% 9% 2 6% 3 3 3 3 4 6% 43%	5028
	11th to 20th	Night	7% 5% 2 5% 3 4 4 4 6% 8% 51%	5090
	21st to end	Night	10% 6% 2 5% 4 4 4 4 5% 6% 51%	5588
April	1st to 10th	Night	9% 4 2 5% 4 4 5% 4 7% 7% 50%	2310
	11th to 20th	Night	8% 5% 2 4 4 3 4 3 6% 8% 53%	2154
	21st to end	Night	6% 5% 2 4 4 3 4 4 6% 8% 54%	1899
May	1st to 10th	Night	6% 5% 2 7% 4 4 5% 4 6% 10% 46%	4033
	11th to 20th	Night	13% 6% 2 5% 4 4 5% 4 7% 9% 41%	4032
	21st to end	Night	7% 4 2 6% 4 4 5% 4 8% 10% 46%	4421
June	1st to 10th	Night	8% 6% 2 6% 5% 5% 5% 6% 9% 13% 33%	1800
	11th to 20th	Night	6% 6% 2 6% 4 5% 7% 5% 8% 12% 38%	1800
	21st to end	Night	5% 5% 2 7% 5% 5% 7% 7% 10% 13% 33%	1800
July	1st to 10th	Night	9% 8% 3 9% 7% 6% 6% 5% 8% 11% 25%	4058
	11th to 20th	Night	3 5% 2 8% 7% 7% 8% 6% 9% 13% 32%	4057
	21st to end	Night	6% 6% 2 8% 6% 6% 7% 6% 10% 11% 31%	4427
August	1st to 10th	Night	16% 5% 3 7% 5% 6% 6% 6% 9% 13% 25%	2915
	11th to 20th	Night	5% 4 2 6% 5% 5% 6% 6% 9% 12% 40%	2875
	21st to end	Night	9% 6% 2 7% 5% 5% 6% 4 7% 11% 37%	3793
September	1st to 10th	Night	10% 6% 3 6% 5% 5% 6% 5% 7% 12% 36%	2200
	11th to 20th	Night	10% 7% 2 8% 5% 6% 6% 5% 7% 9% 37%	2200
	21st to end	Night	12% 6% 3 7% 5% 4 5% 4 6% 7% 41%	2200
October	1st to 10th	Night	11% 7% 2 7% 3 4 4 3 5% 7% 47%	2242
	11th to 20th	Night	9% 5% 2 5% 3 4 3 3 4 4 58%	2400
	21st to end	Night	8% 5% 2 5% 4 3 4 3 4 6% 55%	2640
November	1st to 10th	Night	12% 5% 2 5% 4 3 4 3 4 6% 52%	2461
	11th to 20th	Night	12% 7% 2 5% 4 3 3 3 5% 6% 52%	2598
	21st to end	Night	11% 6% 2 5% 4 4 4 3 6% 7% 48%	2730
December	1st to 10th	Night	9% 5% 2 5% 4 3 3 3 4 6% 56%	4380
	11th to 20th	Night	14% 8% 3 6% 4 3 3 3 4 5% 46%	4952
	21st to end	Night	15% 8% 2 7% 4 4 4 3 4 6% 43%	6633

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	32% 4 9% 18% 27% 9%	5259
	11th to 20th	Day	37% 3 5% 14% 24% 16%	5280
	21st to end	Day	39% 5% 8% 19% 18% 12%	5780
February	1st to 10th	Day	41% 5% 8% 17% 19% 9%	2053
	11th to 20th	Day	39% 4 7% 16% 25% 9%	2058
	21st to end	Day	38% 4 8% 16% 20% 13%	1776
March	1st to 10th	Day	44% 5% 8% 16% 17% 10%	5045
	11th to 20th	Day	27% 5% 11% 16% 18% 23%	5090
	21st to end	Day	39% 4 8% 18% 18% 13%	5586
April	1st to 10th	Day	34% 7% 9% 22% 18% 11%	2310
	11th to 20th	Day	34% 5% 9% 18% 22% 12%	2325
	21st to end	Day	27% 6% 12% 23% 24% 7%	2516
May	1st to 10th	Day	38% 9% 14% 24% 14% 3	5897
	11th to 20th	Day	40% 7% 15% 25% 12% 1	5865
	21st to end	Day	30% 11% 17% 21% 20% 1	6447
June	1st to 10th	Day	45% 12% 13% 18% 12% 1	2600
	11th to 20th	Day	36% 14% 17% 21% 11%	2600
	21st to end	Day	44% 13% 19% 15% 8% 1	2600
July	1st to 10th	Day	53% 18% 18% 9% 2 1	5835
	11th to 20th	Day	36% 19% 30% 12% 2	5831
	21st to end	Day	41% 17% 22% 16% 3	6240
August	1st to 10th	Day	52% 13% 21% 11% 2	4221
	11th to 20th	Day	37% 13% 19% 21% 9%	4213
	21st to end	Day	46% 14% 16% 20% 3	4064
September	1st to 10th	Day	49% 12% 12% 14% 11% 2	2200
	11th to 20th	Day	46% 10% 13% 17% 12% 3	2200
	21st to end	Day	43% 8% 11% 18% 17% 3	2200
October	1st to 10th	Day	46% 5% 8% 10% 16% 14%	3507
	11th to 20th	Day	18% 3 5% 14% 30% 31%	3240
	21st to end	Day	23% 4 6% 18% 34% 15%	3538
November	1st to 10th	Day	32% 4 10% 16% 23% 15%	2057
	11th to 20th	Day	32% 5% 7% 18% 26% 13%	2018
	21st to end	Day	36% 5% 9% 19% 21% 10%	1890
December	1st to 10th	Day	34% 5% 7% 15% 25% 14%	3020
	11th to 20th	Day	37% 4 8% 24% 21% 6%	3460
	21st to end	Day	44% 5% 6% 19% 22% 4	4565
January	1st to 10th	Night	31% 5% 10% 15% 30% 9%	7636
	11th to 20th	Night	36% 4 6% 13% 27% 14%	7680
	21st to end	Night	41% 4 8% 15% 20% 10%	8401
February	1st to 10th	Night	40% 5% 8% 16% 21% 10%	2562
	11th to 20th	Night	42% 5% 7% 17% 18% 12%	2459
	21st to end	Night	37% 4 9% 19% 16% 15%	2029
March	1st to 10th	Night	43% 5% 9% 16% 15% 12%	5028
	11th to 20th	Night	29% 5% 10% 16% 20% 20%	5090
	21st to end	Night	34% 5% 10% 17% 22% 13%	5588
April	1st to 10th	Night	32% 8% 12% 19% 17% 11%	2310
	11th to 20th	Night	29% 6% 9% 23% 22% 12%	2154
	21st to end	Night	26% 7% 12% 27% 22% 7%	1899
May	1st to 10th	Night	32% 10% 16% 26% 12% 3	4060
	11th to 20th	Night	37% 8% 19% 23% 11% 1	4033
	21st to end	Night	30% 10% 15% 27% 16% 1	4429
June	1st to 10th	Night	37% 12% 20% 19% 11% 1	1800
	11th to 20th	Night	33% 14% 21% 23% 8%	1800
	21st to end	Night	35% 16% 25% 16% 7% 1	1800
July	1st to 10th	Night	48% 15% 22% 12% 2	4015
	11th to 20th	Night	39% 16% 32% 11% 2	4006
	21st to end	Night	40% 18% 20% 19% 3	4297
August	1st to 10th	Night	45% 14% 27% 11% 2	2904
	11th to 20th	Night	31% 14% 23% 26% 7%	2902
	21st to end	Night	38% 11% 20% 27% 3	3793
September	1st to 10th	Night	40% 12% 19% 16% 11% 2	2200
	11th to 20th	Night	41% 11% 17% 17% 12% 2	2200
	21st to end	Night	39% 9% 13% 19% 16% 3	2200
October	1st to 10th	Night	40% 6% 11% 12% 19% 12%	3671
	11th to 20th	Night	18% 3 5% 13% 30% 31%	3899
	21st to end	Night	22% 4 7% 16% 34% 17%	4252
November	1st to 10th	Night	34% 5% 8% 15% 24% 14%	2461
	11th to 20th	Night	34% 5% 7% 17% 25% 13%	2598
	21st to end	Night	35% 5% 10% 19% 20% 11%	2730
December	1st to 10th	Night	31% 5% 9% 17% 27% 12%	4380
	11th to 20th	Night	41% 5% 9% 15% 20% 9%	4954
	21st to end	Night	43% 5% 8% 18% 23% 3	6633

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	16% 23% 44% 16% 1 1	330
	11th to 20th	Day	16% 20% 39% 17% 6% 2	330
	21st to end	Day	26% 23% 36% 12% 2	363
February	1st to 10th	Day	18% 22% 38% 17% 4 1	330
	11th to 20th	Day	27% 21% 37% 13% 2	330
	21st to end	Day	20% 18% 42% 16% 3	319
March	1st to 10th	Day	17% 17% 31% 21% 14%	540
	11th to 20th	Day	16% 16% 36% 20% 10% 1	540
	21st to end	Day	15% 18% 34% 22% 9% 2	594
April	1st to 10th	Day	16% 16% 31% 24% 11% 2	540
	11th to 20th	Day	12% 16% 29% 26% 13% 5%	516
	21st to end	Day	9% 10% 31% 27% 16% 7%	500
May	1st to 10th	Day	8% 12% 32% 25% 15% 8%	503
	11th to 20th	Day	10% 6% 28% 30% 16% 10%	527
	21st to end	Day	9% 5% 21% 28% 25% 12%	573
June	1st to 10th	Day	11% 4 20% 28% 25% 11%	530
	11th to 20th	Day	8% 5% 16% 28% 23% 20%	530
	21st to end	Day	8% 2 12% 31% 28% 18%	530
July	1st to 10th	Day	6% 2 11% 24% 34% 23%	525
	11th to 20th	Day	8% 1 5% 23% 37% 26%	524
	21st to end	Day	7% 2 10% 29% 36% 16%	576
August	1st to 10th	Day	13% 4 12% 24% 30% 17%	526
	11th to 20th	Day	5% 2 8% 24% 35% 25%	519
	21st to end	Day	14% 2 13% 27% 25% 19%	583
September	1st to 10th	Day	12% 4 16% 26% 26% 15%	530
	11th to 20th	Day	14% 4 20% 30% 24% 8%	530
	21st to end	Day	15% 4 15% 29% 27% 11%	530
October	1st to 10th	Day	16% 6% 30% 26% 17% 5%	530
	11th to 20th	Day	10% 7% 27% 30% 19% 7%	530
	21st to end	Day	12% 7% 28% 30% 19% 3	583
November	1st to 10th	Day	16% 8% 30% 27% 16% 4	535
	11th to 20th	Day	16% 14% 36% 23% 9% 2	458
	21st to end	Day	14% 16% 37% 26% 7% 1	330
December	1st to 10th	Day	17% 18% 40% 17% 8% 1	330
	11th to 20th	Day	21% 16% 37% 18% 8%	330
	21st to end	Day	22% 12% 36% 24% 6% 1	363
January	1st to 10th	Night	16% 16% 34% 28% 6%	840
	11th to 20th	Night	14% 15% 31% 31% 8% 1	840
	21st to end	Night	20% 15% 38% 23% 4	924
February	1st to 10th	Night	18% 13% 33% 29% 7%	840
	11th to 20th	Night	20% 14% 33% 29% 4	823
	21st to end	Night	13% 14% 39% 29% 4	692
March	1st to 10th	Night	14% 13% 33% 33% 7%	840
	11th to 20th	Night	13% 13% 38% 28% 8%	840
	21st to end	Night	11% 13% 36% 31% 8%	924
April	1st to 10th	Night	12% 11% 36% 33% 8%	840
	11th to 20th	Night	10% 10% 33% 34% 12% 1	816
	21st to end	Night	7% 7% 31% 40% 14%	699
May	1st to 10th	Night	7% 6% 23% 46% 16% 1	600
	11th to 20th	Night	9% 3 25% 39% 21% 3	591
	21st to end	Night	10% 3 16% 37% 31% 4	650
June	1st to 10th	Night	9% 2 15% 41% 30% 3	600
	11th to 20th	Night	8% 2 13% 38% 32% 8%	600
	21st to end	Night	6% 1 12% 41% 33% 8%	600
July	1st to 10th	Night	7% 1 10% 32% 40% 9%	585
	11th to 20th	Night	6% 2 6% 28% 47% 12%	582
	21st to end	Night	4 1 9% 35% 43% 8%	657
August	1st to 10th	Night	9% 1 10% 32% 39% 9%	597
	11th to 20th	Night	7% 1 7% 27% 47% 13%	594
	21st to end	Night	13% 2 12% 29% 33% 10%	827
September	1st to 10th	Night	10% 3 12% 27% 41% 7%	800
	11th to 20th	Night	12% 2 15% 37% 30% 4	800
	21st to end	Night	15% 3 14% 32% 32% 4	800
October	1st to 10th	Night	14% 6% 24% 30% 23% 4	800
	11th to 20th	Night	11% 6% 23% 35% 24% 3	800
	21st to end	Night	11% 7% 24% 34% 23% 1	880
November	1st to 10th	Night	15% 7% 22% 38% 18% 1	820
	11th to 20th	Night	16% 10% 28% 31% 13% 1	840
	21st to end	Night	13% 11% 32% 29% 15%	840
December	1st to 10th	Night	15% 10% 30% 32% 11% 1	840
	11th to 20th	Night	17% 11% 29% 30% 12% 1	840
	21st to end	Night	18% 11% 30% 31% 10%	924

Page generated at 2026-04-14 02:44:29. Version ac07

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