Lawrence
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lawrence clear sky chart from 2005-11-06 to 2024-11-08.

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 6% 4 4 4 4 5% 7% 46%	100977
	Night	11% 7% 2 6% 4 4 4 3 5% 6% 49%	98194
Transparency	Day	36% 6% 12% 26% 17% 3	104627
	Night	34% 5% 12% 26% 19% 3	102671
Seeing	Day	13% 9% 29% 28% 16% 4	15678
	Night	13% 9% 32% 33% 12% 1	25504

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	15% 9% 3 9% 4 3 3 4 6% 6% 37%	2847
	11th to 20th	Day	10% 11% 4 9% 6% 7% 4 3 3 4 39%	2850
	21st to end	Day	13% 16% 6% 8% 3 3 3 3 4 5% 36%	3135
February	1st to 10th	Day	13% 11% 4 7% 5% 4 3 3 4 5% 40%	1710
	11th to 20th	Day	12% 9% 3 8% 5% 4 4 3 5% 5% 43%	1683
	21st to end	Day	11% 9% 2 6% 4 4 5% 4 5% 6% 45%	1611
March	1st to 10th	Day	13% 9% 2 5% 3 3 3 3 4 6% 50%	3436
	11th to 20th	Day	11% 6% 1 5% 3 2 4 3 5% 6% 53%	3480
	21st to end	Day	14% 11% 5% 7% 5% 4 3 3 5% 6% 36%	3814
April	1st to 10th	Day	13% 7% 2 6% 4 3 3 3 4 7% 47%	2166
	11th to 20th	Day	14% 9% 3 6% 4 4 4 4 5% 6% 41%	2254
	21st to end	Day	18% 8% 3 7% 5% 5% 4 3 4 6% 37%	2456
May	1st to 10th	Day	15% 10% 3 7% 4 4 4 3 4 6% 40%	4082
	11th to 20th	Day	15% 7% 3 6% 4 4 4 4 6% 8% 39%	4082
	21st to end	Day	12% 6% 3 6% 4 4 3 4 6% 7% 44%	4477
June	1st to 10th	Day	6% 4 1 5% 3 4 5% 5% 7% 10% 49%	2617
	11th to 20th	Day	6% 5% 2 5% 4 5% 4 5% 7% 9% 48%	2660
	21st to end	Day	7% 4 2 4 3 4 5% 4 6% 9% 51%	2543
July	1st to 10th	Day	10% 6% 2 6% 4 4 5% 4 7% 8% 42%	4120
	11th to 20th	Day	5% 3 2 4 3 4 4 4 7% 10% 54%	4120
	21st to end	Day	6% 4 1 4 4 4 5% 5% 8% 11% 49%	4465
August	1st to 10th	Day	5% 4 2 5% 4 4 4 4 6% 8% 53%	4104
	11th to 20th	Day	11% 5% 2 6% 4 4 4 4 6% 7% 47%	4041
	21st to end	Day	6% 3 2 5% 3 4 4 3 5% 9% 56%	4318
September	1st to 10th	Day	12% 4 2 4 3 3 3 3 5% 7% 54%	2251
	11th to 20th	Day	8% 5% 2 6% 4 4 4 4 6% 7% 50%	2090
	21st to end	Day	8% 5% 1 6% 4 3 4 4 6% 6% 54%	2090
October	1st to 10th	Day	11% 5% 1 5% 4 2 3 3 5% 6% 54%	1914
	11th to 20th	Day	12% 6% 2 5% 3 3 2 2 4 5% 57%	1900
	21st to end	Day	16% 5% 2 5% 3 3 3 3 4 5% 50%	2090
November	1st to 10th	Day	9% 6% 2 5% 3 3 3 3 5% 6% 54%	1890
	11th to 20th	Day	12% 6% 2 4 3 4 3 3 3 6% 54%	1702
	21st to end	Day	15% 8% 2 5% 3 3 2 3 4 5% 49%	1520
December	1st to 10th	Day	9% 7% 3 5% 5% 4 4 3 6% 7% 48%	1520
	11th to 20th	Day	12% 9% 4 8% 5% 4 5% 3 4 6% 41%	1918
	21st to end	Day	15% 16% 7% 12% 5% 3 3 3 4 6% 26%	3021
January	1st to 10th	Night	8% 10% 4 14% 6% 4 3 3 3 5% 40%	4108
	11th to 20th	Night	10% 11% 4 9% 5% 6% 5% 3 4 5% 39%	4120
	21st to end	Night	17% 12% 4 9% 4 3 4 3 4 5% 36%	4532
February	1st to 10th	Night	10% 12% 3 8% 5% 4 3 3 5% 6% 40%	2470
	11th to 20th	Night	11% 9% 2 6% 4 5% 4 3 5% 6% 44%	2399
	21st to end	Night	11% 7% 3 6% 4 4 5% 3 4 5% 48%	1841
March	1st to 10th	Night	12% 7% 2 5% 3 3 3 2 4 5% 53%	3419
	11th to 20th	Night	10% 6% 2 4 2 3 3 2 5% 7% 56%	3480
	21st to end	Night	16% 9% 2 7% 4 4 4 3 5% 6% 39%	3817
April	1st to 10th	Night	11% 6% 2 5% 4 3 4 3 5% 6% 51%	2012
	11th to 20th	Night	12% 8% 2 6% 4 4 4 3 4 7% 47%	1875
	21st to end	Night	17% 6% 2 5% 4 4 4 3 5% 6% 43%	1720
May	1st to 10th	Night	15% 8% 2 5% 4 4 4 4 7% 7% 39%	2823
	11th to 20th	Night	14% 7% 2 6% 3 3 4 3 5% 8% 44%	2823
	21st to end	Night	10% 5% 2 4 3 3 3 3 5% 7% 53%	3090
June	1st to 10th	Night	6% 3 1 4 4 5% 4 4 6% 9% 56%	1558
	11th to 20th	Night	5% 3 1 4 4 4 5% 4 7% 10% 52%	1520
	21st to end	Night	4 3 1 4 3 2 3 4 6% 10% 61%	1627
July	1st to 10th	Night	10% 6% 2 6% 4 4 4 3 5% 7% 49%	2850
	11th to 20th	Night	1 2 1 3 4 3 4 4 6% 10% 60%	2850
	21st to end	Night	6% 3 2 5% 4 4 5% 4 8% 11% 50%	3098
August	1st to 10th	Night	2 2 1 3 3 4 4 4 8% 10% 59%	2836
	11th to 20th	Night	10% 5% 2 6% 4 4 3 3 5% 7% 51%	2798
	21st to end	Night	4 4 2 5% 4 3 3 3 6% 7% 59%	3342
September	1st to 10th	Night	10% 5% 1 5% 3 3 3 3 4 5% 57%	1926
	11th to 20th	Night	8% 4 2 4 2 3 4 5% 5% 7% 55%	2090
	21st to end	Night	7% 4 2 5% 4 3 4 3 4 6% 59%	2090
October	1st to 10th	Night	11% 4 1 4 3 3 4 3 4 5% 57%	2247
	11th to 20th	Night	12% 5% 1 4 2 3 3 2 4 6% 58%	2280
	21st to end	Night	14% 7% 2 5% 3 3 3 2 3 4 52%	2508
November	1st to 10th	Night	9% 5% 1 4 2 2 3 2 4 6% 61%	2344
	11th to 20th	Night	10% 5% 2 4 3 3 3 3 5% 6% 55%	2474
	21st to end	Night	14% 7% 2 3 2 2 4 2 4 6% 53%	2660
December	1st to 10th	Night	9% 8% 3 5% 4 4 4 4 5% 5% 48%	2660
	11th to 20th	Night	12% 9% 3 6% 3 4 3 3 5% 6% 46%	3279
	21st to end	Night	18% 17% 5% 8% 4 4 4 2 3 4 31%	4628

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	47% 5% 11% 24% 12% 1	2848
	11th to 20th	Day	50% 3 14% 20% 12% 1	2850
	21st to end	Day	52% 4 12% 18% 14% 1	3135
February	1st to 10th	Day	47% 4 13% 22% 10% 3	1710
	11th to 20th	Day	43% 4 12% 23% 15% 2	1692
	21st to end	Day	39% 5% 11% 24% 16% 4	1611
March	1st to 10th	Day	37% 4 11% 21% 22% 4	3436
	11th to 20th	Day	31% 5% 13% 28% 21% 3	3480
	21st to end	Day	48% 6% 14% 25% 6% 1	3814
April	1st to 10th	Day	39% 5% 12% 22% 19% 3	2166
	11th to 20th	Day	43% 5% 12% 22% 17% 1	2254
	21st to end	Day	48% 6% 11% 23% 11% 1	2456
May	1st to 10th	Day	45% 7% 10% 23% 14% 2	4120
	11th to 20th	Day	41% 8% 13% 22% 15%	4086
	21st to end	Day	37% 7% 12% 29% 13% 2	4489
June	1st to 10th	Day	27% 9% 17% 29% 16% 2	2617
	11th to 20th	Day	30% 9% 14% 29% 17% 2	2660
	21st to end	Day	28% 7% 15% 29% 17% 3	2543
July	1st to 10th	Day	37% 8% 14% 22% 17% 3	4056
	11th to 20th	Day	24% 7% 13% 35% 19% 2	4051
	21st to end	Day	25% 9% 18% 31% 15% 2	4325
August	1st to 10th	Day	28% 7% 13% 28% 21% 3	4090
	11th to 20th	Day	35% 6% 16% 26% 16% 1	4080
	21st to end	Day	26% 6% 17% 31% 15% 6%	4317
September	1st to 10th	Day	30% 5% 11% 26% 20% 7%	2251
	11th to 20th	Day	32% 7% 11% 26% 21% 3	2090
	21st to end	Day	30% 6% 9% 28% 24% 3	2090
October	1st to 10th	Day	19% 3 7% 23% 41% 7%	3174
	11th to 20th	Day	19% 3 5% 28% 36% 10%	3140
	21st to end	Day	30% 4 11% 25% 25% 3	3428
November	1st to 10th	Day	30% 5% 13% 29% 18% 5%	1890
	11th to 20th	Day	33% 4 10% 29% 21% 3	1702
	21st to end	Day	39% 3 9% 26% 22% 1	1520
December	1st to 10th	Day	36% 5% 14% 31% 13% 1	1520
	11th to 20th	Day	45% 5% 12% 25% 11% 2	1915
	21st to end	Day	60% 5% 10% 16% 8% 1	3021
January	1st to 10th	Night	47% 5% 14% 21% 12% 1	4108
	11th to 20th	Night	49% 4 12% 21% 14% 1	4120
	21st to end	Night	51% 4 13% 19% 11% 1	4532
February	1st to 10th	Night	46% 4 12% 21% 14% 3	2470
	11th to 20th	Night	41% 4 12% 23% 17% 3	2400
	21st to end	Night	38% 4 9% 21% 20% 7%	1841
March	1st to 10th	Night	34% 5% 9% 26% 23% 3	3419
	11th to 20th	Night	29% 4 10% 26% 27% 4	3480
	21st to end	Night	44% 7% 17% 23% 8% 1	3817
April	1st to 10th	Night	34% 5% 11% 24% 21% 5%	2012
	11th to 20th	Night	38% 4 10% 27% 18% 3	1875
	21st to end	Night	41% 6% 12% 25% 15% 2	1720
May	1st to 10th	Night	39% 9% 16% 20% 14% 2	2850
	11th to 20th	Night	38% 7% 13% 26% 16% 1	2824
	21st to end	Night	29% 7% 13% 31% 19% 1	3099
June	1st to 10th	Night	23% 9% 17% 32% 16% 4	1558
	11th to 20th	Night	24% 8% 14% 33% 19% 2	1520
	21st to end	Night	19% 6% 15% 35% 21% 4	1627
July	1st to 10th	Night	34% 7% 12% 24% 20% 4	2805
	11th to 20th	Night	17% 7% 15% 35% 23% 3	2796
	21st to end	Night	25% 8% 20% 30% 17% 1	2999
August	1st to 10th	Night	18% 8% 18% 28% 22% 6%	2826
	11th to 20th	Night	32% 6% 13% 27% 19% 2	2825
	21st to end	Night	23% 5% 13% 37% 17% 5%	3342
September	1st to 10th	Night	29% 5% 10% 26% 21% 9%	1926
	11th to 20th	Night	27% 6% 11% 26% 25% 4	2090
	21st to end	Night	26% 6% 8% 26% 30% 4	2090
October	1st to 10th	Night	19% 4 6% 19% 47% 7%	3754
	11th to 20th	Night	21% 2 5% 27% 31% 13%	3779
	21st to end	Night	33% 3 7% 29% 25% 2	4120
November	1st to 10th	Night	27% 3 13% 27% 24% 6%	2344
	11th to 20th	Night	30% 4 10% 28% 23% 4	2474
	21st to end	Night	34% 4 10% 29% 20% 3	2660
December	1st to 10th	Night	37% 6% 12% 27% 17% 1	2660
	11th to 20th	Night	40% 3 11% 29% 15% 2	3281
	21st to end	Night	58% 5% 8% 19% 9% 2	4628

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% 17% 32% 25% 6%	270
	11th to 20th	Day	24% 18% 39% 16% 3	270
	21st to end	Day	13% 11% 48% 23% 4	297
February	1st to 10th	Day	20% 23% 36% 19% 1 1	270
	11th to 20th	Day	19% 16% 46% 13% 7%	270
	21st to end	Day	15% 27% 39% 17% 2	225
March	1st to 10th	Day	13% 16% 45% 21% 4	270
	11th to 20th	Day	26% 13% 36% 19% 6%	270
	21st to end	Day	30% 17% 35% 14% 3 1	297
April	1st to 10th	Day	21% 18% 34% 21% 7%	346
	11th to 20th	Day	18% 15% 38% 23% 6% 1	452
	21st to end	Day	23% 14% 34% 19% 9% 1	636
May	1st to 10th	Day	18% 15% 35% 22% 9% 1	653
	11th to 20th	Day	18% 9% 28% 31% 12% 2	675
	21st to end	Day	16% 8% 29% 27% 16% 3	734
June	1st to 10th	Day	5% 5% 21% 36% 26% 7%	680
	11th to 20th	Day	7% 3 28% 38% 20% 5%	680
	21st to end	Day	7% 7% 32% 37% 16% 2	680
July	1st to 10th	Day	9% 4 15% 31% 31% 10%	671
	11th to 20th	Day	4 2 20% 35% 30% 9%	668
	21st to end	Day	8% 2 16% 34% 31% 9%	739
August	1st to 10th	Day	6% 2 16% 41% 29% 5%	676
	11th to 20th	Day	8% 4 16% 40% 26% 6%	665
	21st to end	Day	8% 1 16% 32% 34% 9%	625
September	1st to 10th	Day	12% 2 18% 34% 28% 6%	461
	11th to 20th	Day	5% 3 23% 36% 27% 5%	300
	21st to end	Day	13% 6% 26% 35% 15% 5%	300
October	1st to 10th	Day	15% 7% 27% 26% 18% 8%	300
	11th to 20th	Day	10% 18% 39% 23% 9% 1	300
	21st to end	Day	22% 15% 35% 19% 8% 1	330
November	1st to 10th	Day	14% 12% 38% 24% 8% 3	291
	11th to 20th	Day	14% 19% 33% 24% 8% 1	270
	21st to end	Day	22% 14% 35% 20% 9%	270
December	1st to 10th	Day	8% 14% 40% 29% 6% 3	270
	11th to 20th	Day	18% 14% 37% 22% 7% 1	270
	21st to end	Day	21% 21% 39% 17% 2	297
January	1st to 10th	Night	13% 13% 36% 30% 7%	950
	11th to 20th	Night	16% 13% 38% 27% 6% 1	950
	21st to end	Night	15% 13% 40% 29% 4	1045
February	1st to 10th	Night	18% 13% 41% 26% 3	950
	11th to 20th	Night	16% 14% 39% 28% 3	925
	21st to end	Night	18% 12% 41% 24% 5%	585
March	1st to 10th	Night	14% 12% 44% 25% 5%	570
	11th to 20th	Night	18% 11% 37% 28% 5% 1	570
	21st to end	Night	23% 13% 35% 24% 4	627
April	1st to 10th	Night	14% 11% 41% 28% 5% 1	570
	11th to 20th	Night	16% 14% 35% 30% 5%	563
	21st to end	Night	19% 11% 36% 26% 8% 1	570
May	1st to 10th	Night	17% 8% 33% 34% 8% 1	570
	11th to 20th	Night	16% 5% 30% 35% 13%	561
	21st to end	Night	10% 6% 29% 36% 16% 2	617
June	1st to 10th	Night	5% 4 22% 43% 25% 1	570
	11th to 20th	Night	6% 3 28% 44% 17% 2	570
	21st to end	Night	5% 4 29% 48% 14% 1	570
July	1st to 10th	Night	8% 2 14% 43% 31% 3	555
	11th to 20th	Night	2 2 16% 50% 28% 2	552
	21st to end	Night	8% 2 14% 47% 27% 1	624
August	1st to 10th	Night	4 2 15% 49% 29% 1	567
	11th to 20th	Night	7% 2 13% 45% 30% 3	564
	21st to end	Night	7% 1 13% 42% 35% 2	627
September	1st to 10th	Night	13% 3 18% 41% 23% 2	570
	11th to 20th	Night	8% 3 22% 40% 24% 2	570
	21st to end	Night	7% 4 25% 43% 19% 2	570
October	1st to 10th	Night	12% 4 28% 33% 22% 1	727
	11th to 20th	Night	14% 9% 38% 30% 9%	760
	21st to end	Night	18% 12% 34% 28% 8%	836
November	1st to 10th	Night	11% 10% 33% 34% 11% 1	804
	11th to 20th	Night	12% 14% 37% 28% 8%	950
	21st to end	Night	18% 10% 34% 30% 7%	950
December	1st to 10th	Night	14% 12% 35% 31% 6% 1	950
	11th to 20th	Night	18% 9% 39% 28% 5%	950
	21st to end	Night	20% 13% 36% 26% 4	1045

Page generated at 2024-11-05 07:15:53. Version ac07

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