ROBOsky.com Wild Flower Ridge Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the ROBOsky.com Wild Flower Ridge Observatory clear sky chart from 2005-11-06 to 2025-09-04.

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% 11% 4 9% 6% 5% 5% 4 6% 7% 30%	127009
	Night	13% 11% 4 10% 6% 5% 5% 4 5% 6% 31%	121678
Transparency	Day	50% 8% 12% 19% 10% 1	130602
	Night	49% 8% 12% 19% 11% 1	126175
Seeing	Day	21% 20% 31% 18% 8% 3	15915
	Night	19% 19% 31% 22% 8% 1	24815

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	12% 13% 6% 19% 7% 6% 7% 4 5% 5% 18%	3597
	11th to 20th	Day	8% 18% 8% 20% 11% 9% 5% 4 5% 4 8%	3958
	21st to end	Day	15% 18% 7% 16% 7% 6% 6% 4 4 5% 13%	4466
February	1st to 10th	Day	12% 17% 5% 15% 10% 6% 5% 3 4 5% 17%	1800
	11th to 20th	Day	11% 13% 7% 16% 10% 4 5% 4 6% 5% 19%	1753
	21st to end	Day	15% 17% 5% 11% 6% 4 5% 4 6% 5% 21%	1550
March	1st to 10th	Day	15% 12% 5% 11% 8% 5% 4 3 4 4 29%	4924
	11th to 20th	Day	9% 13% 6% 11% 6% 4 5% 3 6% 8% 28%	4980
	21st to end	Day	15% 14% 5% 9% 5% 5% 4 3 4 5% 32%	5465
April	1st to 10th	Day	15% 16% 5% 9% 5% 4 4 3 5% 6% 28%	2340
	11th to 20th	Day	17% 12% 4 7% 4 4 4 3 6% 6% 35%	2489
	21st to end	Day	19% 11% 4 8% 4 4 3 3 6% 6% 33%	2600
May	1st to 10th	Day	18% 9% 3 7% 4 4 4 4 5% 7% 35%	5888
	11th to 20th	Day	16% 9% 3 8% 5% 5% 5% 4 6% 6% 33%	6221
	21st to end	Day	17% 7% 3 6% 5% 4 4 3 5% 7% 38%	6949
June	1st to 10th	Day	15% 6% 2 7% 5% 5% 4 5% 6% 9% 36%	2800
	11th to 20th	Day	12% 6% 2 6% 5% 5% 5% 4 7% 9% 39%	2910
	21st to end	Day	14% 6% 3 6% 5% 5% 5% 3 6% 10% 38%	3000
July	1st to 10th	Day	10% 5% 2 7% 6% 6% 6% 5% 7% 9% 36%	6759
	11th to 20th	Day	8% 5% 2 6% 4 5% 5% 4 7% 9% 44%	6346
	21st to end	Day	8% 5% 2 6% 4 5% 5% 4 6% 9% 46%	6424
August	1st to 10th	Day	14% 7% 3 7% 4 5% 5% 5% 7% 8% 35%	4234
	11th to 20th	Day	12% 7% 4 8% 6% 6% 6% 5% 7% 9% 32%	4174
	21st to end	Day	10% 7% 2 6% 4 5% 6% 4 6% 9% 40%	4543
September	1st to 10th	Day	14% 7% 2 7% 5% 5% 5% 4 6% 7% 39%	2316
	11th to 20th	Day	12% 7% 2 6% 5% 5% 5% 3 5% 8% 42%	2136
	21st to end	Day	15% 7% 3 8% 7% 5% 5% 4 6% 7% 32%	2071
October	1st to 10th	Day	18% 10% 3 8% 4 6% 4 4 5% 6% 32%	1900
	11th to 20th	Day	18% 13% 4 10% 5% 4 4 3 5% 5% 27%	1900
	21st to end	Day	25% 17% 4 8% 5% 4 4 4 4 6% 20%	2090
November	1st to 10th	Day	11% 16% 4 10% 6% 5% 4 4 5% 7% 28%	1680
	11th to 20th	Day	12% 16% 5% 12% 6% 6% 6% 4 5% 7% 22%	1600
	21st to end	Day	14% 19% 6% 12% 7% 5% 5% 4 5% 7% 16%	1600
December	1st to 10th	Day	16% 20% 8% 14% 7% 6% 5% 4 5% 5% 10%	2600
	11th to 20th	Day	18% 21% 6% 11% 6% 4 4 3 5% 5% 17%	2986
	21st to end	Day	21% 20% 7% 16% 7% 5% 5% 3 4 3 9%	3960
January	1st to 10th	Night	12% 12% 7% 16% 9% 7% 6% 3 4 5% 19%	6349
	11th to 20th	Night	10% 13% 8% 18% 13% 9% 6% 4 5% 4 10%	5923
	21st to end	Night	13% 13% 6% 13% 7% 7% 7% 4 6% 7% 17%	6490
February	1st to 10th	Night	12% 14% 5% 13% 8% 5% 5% 4 6% 6% 21%	2600
	11th to 20th	Night	10% 13% 5% 13% 8% 8% 5% 4 6% 5% 22%	2533
	21st to end	Night	11% 13% 5% 11% 7% 6% 6% 5% 5% 7% 25%	2075
March	1st to 10th	Night	12% 11% 5% 10% 6% 5% 5% 5% 7% 7% 27%	4915
	11th to 20th	Night	8% 9% 4 9% 5% 5% 5% 5% 7% 8% 34%	4979
	21st to end	Night	16% 10% 3 8% 5% 4 4 3 5% 6% 36%	5467
April	1st to 10th	Night	17% 14% 4 8% 5% 4 4 3 4 6% 30%	2059
	11th to 20th	Night	16% 10% 2 5% 5% 4 5% 4 5% 7% 37%	1877
	21st to end	Night	14% 11% 4 7% 5% 4 4 4 5% 6% 34%	1800
May	1st to 10th	Night	18% 9% 3 7% 4 4 5% 4 5% 6% 37%	4053
	11th to 20th	Night	14% 7% 2 6% 4 4 4 4 6% 7% 41%	3669
	21st to end	Night	16% 6% 2 6% 3 3 3 3 5% 7% 45%	3926
June	1st to 10th	Night	12% 6% 2 6% 4 5% 5% 4 5% 9% 42%	1600
	11th to 20th	Night	8% 5% 2 7% 5% 4 6% 4 7% 10% 42%	1483
	21st to end	Night	11% 6% 3 5% 4 4 4 4 6% 7% 48%	1400
July	1st to 10th	Night	7% 6% 3 7% 5% 4 5% 4 5% 8% 48%	3199
	11th to 20th	Night	9% 5% 2 5% 4 4 4 4 5% 7% 51%	3600
	21st to end	Night	7% 5% 2 5% 4 4 4 4 6% 8% 52%	4424
August	1st to 10th	Night	10% 5% 2 6% 3 4 4 4 6% 6% 50%	2915
	11th to 20th	Night	12% 5% 2 5% 3 4 4 3 5% 8% 48%	2875
	21st to end	Night	10% 6% 1 6% 4 4 5% 3 5% 7% 49%	3321
September	1st to 10th	Night	8% 5% 2 6% 4 4 5% 4 6% 7% 49%	1931
	11th to 20th	Night	10% 4 2 5% 3 3 3 3 6% 6% 54%	2042
	21st to end	Night	15% 8% 3 7% 4 4 3 3 5% 7% 41%	2109
October	1st to 10th	Night	16% 8% 2 8% 5% 4 5% 3 5% 6% 38%	2280
	11th to 20th	Night	17% 11% 4 7% 5% 4 5% 3 5% 5% 34%	2280
	21st to end	Night	19% 12% 3 8% 6% 4 5% 4 6% 7% 25%	2508
November	1st to 10th	Night	14% 11% 3 7% 5% 5% 5% 5% 5% 6% 33%	2612
	11th to 20th	Night	14% 14% 4 10% 5% 5% 5% 4 6% 8% 25%	2800
	21st to end	Night	15% 16% 5% 10% 7% 4 5% 4 6% 6% 22%	2800
December	1st to 10th	Night	15% 16% 7% 13% 6% 7% 6% 5% 5% 6% 13%	4580
	11th to 20th	Night	12% 19% 8% 14% 7% 5% 5% 4 5% 4 16%	5208
	21st to end	Night	21% 20% 7% 17% 6% 5% 4 3 4 4 10%	6996

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	64% 9% 10% 12% 5%	3598
	11th to 20th	Day	74% 8% 7% 7% 4 1	3992
	21st to end	Day	70% 8% 9% 8% 4	4466
February	1st to 10th	Day	69% 8% 7% 12% 3 1	1800
	11th to 20th	Day	63% 9% 11% 12% 5% 1	1762
	21st to end	Day	61% 8% 10% 13% 7% 1	1550
March	1st to 10th	Day	56% 7% 12% 12% 12% 1	4927
	11th to 20th	Day	51% 7% 14% 19% 6% 3	4980
	21st to end	Day	53% 6% 10% 17% 12% 2	5465
April	1st to 10th	Day	56% 6% 9% 17% 10% 1	2340
	11th to 20th	Day	49% 6% 10% 21% 13% 1	2489
	21st to end	Day	51% 7% 11% 18% 11% 2	2600
May	1st to 10th	Day	45% 8% 13% 18% 10% 5%	5897
	11th to 20th	Day	47% 10% 11% 15% 16% 1	6225
	21st to end	Day	44% 7% 11% 20% 15% 3	6949
June	1st to 10th	Day	42% 9% 13% 20% 15% 1	2800
	11th to 20th	Day	38% 9% 13% 24% 15% 1	2910
	21st to end	Day	41% 8% 14% 23% 13% 1	3000
July	1st to 10th	Day	41% 7% 14% 22% 15% 1	6687
	11th to 20th	Day	33% 7% 12% 32% 15% 1	6271
	21st to end	Day	33% 8% 13% 30% 16% 1	6240
August	1st to 10th	Day	44% 8% 14% 23% 11% 1	4221
	11th to 20th	Day	45% 7% 16% 23% 8%	4213
	21st to end	Day	38% 9% 13% 31% 9% 1	4543
September	1st to 10th	Day	42% 9% 13% 24% 10% 2	2316
	11th to 20th	Day	39% 6% 14% 27% 13%	2136
	21st to end	Day	48% 9% 13% 22% 8%	2071
October	1st to 10th	Day	45% 8% 12% 24% 11% 1	3160
	11th to 20th	Day	45% 8% 13% 20% 14% 1	3140
	21st to end	Day	59% 7% 12% 16% 6%	3428
November	1st to 10th	Day	53% 9% 14% 16% 8%	1680
	11th to 20th	Day	59% 9% 12% 12% 7% 1	1600
	21st to end	Day	66% 9% 12% 10% 3	1600
December	1st to 10th	Day	73% 8% 11% 5% 2	2600
	11th to 20th	Day	69% 7% 9% 8% 6%	2986
	21st to end	Day	78% 7% 5% 5% 4	3960
January	1st to 10th	Night	63% 10% 10% 13% 4	6349
	11th to 20th	Night	70% 10% 8% 8% 3	5964
	21st to end	Night	60% 10% 11% 9% 8% 1	6490
February	1st to 10th	Night	59% 9% 11% 16% 5%	2600
	11th to 20th	Night	60% 7% 11% 14% 6%	2535
	21st to end	Night	55% 10% 13% 15% 8% 1	2075
March	1st to 10th	Night	51% 8% 13% 16% 10% 2	4925
	11th to 20th	Night	41% 10% 18% 21% 8% 2	4980
	21st to end	Night	47% 7% 11% 20% 14% 2	5467
April	1st to 10th	Night	55% 6% 10% 17% 12% 1	2059
	11th to 20th	Night	45% 7% 10% 21% 15% 1	1877
	21st to end	Night	47% 7% 12% 16% 16% 2	1800
May	1st to 10th	Night	46% 7% 13% 14% 14% 7%	4060
	11th to 20th	Night	39% 10% 13% 22% 14% 2	3670
	21st to end	Night	37% 8% 13% 25% 15% 2	3927
June	1st to 10th	Night	37% 8% 13% 24% 17% 2	1600
	11th to 20th	Night	34% 9% 14% 24% 18% 1	1483
	21st to end	Night	35% 9% 13% 26% 16% 1	1400
July	1st to 10th	Night	33% 7% 14% 25% 18% 2	3164
	11th to 20th	Night	31% 7% 11% 31% 19% 1	3552
	21st to end	Night	30% 7% 12% 32% 17% 2	4294
August	1st to 10th	Night	34% 6% 13% 29% 16% 2	2904
	11th to 20th	Night	34% 7% 15% 30% 13% 1	2902
	21st to end	Night	33% 7% 13% 32% 14% 1	3321
September	1st to 10th	Night	32% 8% 17% 29% 13% 1	1931
	11th to 20th	Night	28% 7% 14% 32% 19%	2042
	21st to end	Night	43% 7% 13% 26% 10% 1	2109
October	1st to 10th	Night	36% 7% 8% 26% 21% 1	3800
	11th to 20th	Night	44% 7% 11% 22% 14% 2	3779
	21st to end	Night	47% 8% 14% 23% 8%	4120
November	1st to 10th	Night	48% 9% 14% 20% 9% 1	2612
	11th to 20th	Night	53% 10% 14% 15% 7% 1	2800
	21st to end	Night	59% 11% 15% 12% 2 1	2800
December	1st to 10th	Night	67% 10% 13% 8% 2	4580
	11th to 20th	Night	66% 8% 9% 10% 7%	5208
	21st to end	Night	75% 8% 6% 7% 3	6996

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	24% 28% 33% 13% 3 1	200
	11th to 20th	Day	23% 33% 30% 10% 3	286
	21st to end	Day	28% 29% 32% 10% 2	330
February	1st to 10th	Day	31% 34% 26% 8% 2	300
	11th to 20th	Day	30% 31% 34% 4 1	300
	21st to end	Day	35% 35% 24% 5%	249
March	1st to 10th	Day	24% 29% 31% 13% 3	492
	11th to 20th	Day	27% 24% 35% 11% 4	500
	21st to end	Day	31% 23% 29% 13% 4	550
April	1st to 10th	Day	27% 25% 33% 10% 4	500
	11th to 20th	Day	33% 23% 23% 11% 7% 2	492
	21st to end	Day	28% 23% 31% 13% 5% 2	500
May	1st to 10th	Day	23% 19% 32% 17% 7% 2	503
	11th to 20th	Day	21% 15% 33% 18% 9% 3	527
	21st to end	Day	16% 17% 31% 24% 9% 3	573
June	1st to 10th	Day	17% 18% 36% 21% 7% 2	530
	11th to 20th	Day	15% 15% 33% 26% 9% 2	640
	21st to end	Day	17% 15% 37% 22% 7% 2	730
July	1st to 10th	Day	12% 11% 33% 27% 14% 3	701
	11th to 20th	Day	13% 10% 33% 27% 11% 6%	524
	21st to end	Day	9% 11% 39% 25% 11% 5%	576
August	1st to 10th	Day	9% 10% 29% 31% 15% 6%	526
	11th to 20th	Day	9% 10% 30% 26% 17% 7%	519
	21st to end	Day	14% 12% 31% 24% 14% 5%	583
September	1st to 10th	Day	14% 12% 32% 24% 11% 7%	502
	11th to 20th	Day	10% 11% 25% 25% 18% 10%	490
	21st to end	Day	17% 16% 28% 21% 14% 4	490
October	1st to 10th	Day	23% 21% 24% 19% 10% 4	490
	11th to 20th	Day	23% 23% 33% 14% 5% 1	490
	21st to end	Day	34% 24% 27% 13% 2	539
November	1st to 10th	Day	26% 26% 29% 15% 3 1	263
	11th to 20th	Day	27% 26% 33% 8% 5% 2	200
	21st to end	Day	26% 26% 39% 9% 1	200
December	1st to 10th	Day	32% 29% 31% 9% 1	200
	11th to 20th	Day	32% 30% 26% 11% 1 1	200
	21st to end	Day	30% 30% 30% 7% 2	220
January	1st to 10th	Night	21% 32% 32% 12% 3	800
	11th to 20th	Night	25% 24% 32% 16% 2	800
	21st to end	Night	18% 22% 35% 19% 5%	880
February	1st to 10th	Night	22% 30% 32% 15% 1	800
	11th to 20th	Night	23% 25% 36% 13% 3	783
	21st to end	Night	21% 28% 35% 14% 2	660
March	1st to 10th	Night	21% 26% 34% 17% 3	800
	11th to 20th	Night	22% 26% 31% 16% 4	800
	21st to end	Night	22% 20% 33% 19% 5%	880
April	1st to 10th	Night	26% 21% 34% 18% 2	800
	11th to 20th	Night	22% 19% 33% 18% 6% 1	693
	21st to end	Night	22% 16% 33% 22% 7%	600
May	1st to 10th	Night	18% 11% 32% 29% 9% 2	600
	11th to 20th	Night	18% 10% 34% 27% 9% 1	436
	21st to end	Night	12% 11% 33% 32% 12%	433
June	1st to 10th	Night	15% 9% 38% 30% 9% 1	400
	11th to 20th	Night	10% 12% 31% 36% 12%	400
	21st to end	Night	14% 9% 33% 31% 13%	400
July	1st to 10th	Night	5% 7% 31% 39% 17% 1	390
	11th to 20th	Night	9% 10% 29% 34% 18% 1	388
	21st to end	Night	8% 7% 32% 36% 17% 1	653
August	1st to 10th	Night	10% 4 26% 38% 22% 2	597
	11th to 20th	Night	8% 6% 24% 39% 22% 2	594
	21st to end	Night	13% 7% 30% 27% 20% 2	719
September	1st to 10th	Night	11% 10% 28% 29% 18% 5%	773
	11th to 20th	Night	12% 9% 26% 28% 21% 5%	760
	21st to end	Night	19% 11% 25% 27% 15% 3	760
October	1st to 10th	Night	18% 13% 34% 20% 13% 2	760
	11th to 20th	Night	25% 17% 32% 20% 6% 1	760
	21st to end	Night	25% 23% 29% 19% 3	836
November	1st to 10th	Night	22% 20% 31% 20% 7% 1	780
	11th to 20th	Night	21% 28% 28% 18% 5% 1	800
	21st to end	Night	24% 24% 33% 16% 3	800
December	1st to 10th	Night	28% 26% 31% 13% 3	800
	11th to 20th	Night	22% 29% 34% 12% 3	800
	21st to end	Night	29% 25% 30% 14% 2	880

Page generated at 2025-09-01 01:51:05. Version ac07

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