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 2024-05-14.

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% 8% 3 6% 4 4 4 3 5% 7% 45%	83695
	Night	11% 7% 2 6% 4 4 4 3 5% 6% 48%	85853
Transparency	Day	38% 6% 13% 25% 16% 2	83418
	Night	36% 5% 12% 26% 18% 3	85650
Seeing	Day	14% 10% 28% 28% 16% 4	14924
	Night	13% 9% 32% 33% 12% 1	24932

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	16% 11% 3 7% 5% 4 4 3 5% 6% 37%	2470
	11th to 20th	Day	15% 7% 3 6% 5% 4 4 3 5% 7% 40%	2342
	21st to end	Day	14% 8% 3 7% 5% 6% 4 4 7% 7% 35%	2531
June	1st to 10th	Day	6% 4 1 5% 3 4 5% 5% 7% 10% 49%	2479
	11th to 20th	Day	6% 5% 2 5% 4 5% 4 5% 7% 9% 49%	2520
	21st to end	Day	7% 4 2 4 3 4 5% 4 6% 9% 52%	2410
July	1st to 10th	Day	9% 4 2 5% 4 4 5% 4 7% 9% 45%	2340
	11th to 20th	Day	4 3 1 5% 4 5% 5% 5% 7% 9% 54%	2340
	21st to end	Day	8% 5% 2 5% 5% 4 4 4 7% 10% 46%	2546
August	1st to 10th	Day	7% 4 2 6% 5% 4 5% 5% 7% 10% 46%	2328
	11th to 20th	Day	7% 5% 2 5% 4 4 4 4 6% 7% 52%	2301
	21st to end	Day	8% 3 2 5% 4 4 4 3 5% 8% 53%	2458
September	1st to 10th	Day	13% 4 2 4 3 3 3 3 5% 7% 52%	2133
	11th to 20th	Day	8% 5% 2 6% 4 4 4 4 6% 7% 50%	1980
	21st to end	Day	8% 5% 2 5% 4 3 4 4 6% 6% 55%	1980
October	1st to 10th	Day	12% 6% 1 5% 4 2 3 3 5% 7% 51%	1814
	11th to 20th	Day	12% 6% 2 5% 3 3 2 2 4 5% 56%	1800
	21st to end	Day	16% 6% 2 5% 3 3 3 3 4 6% 49%	1980
November	1st to 10th	Day	9% 6% 2 5% 3 3 3 3 5% 6% 55%	1820
	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% 3 5% 4 4 4 4 6% 8% 40%	1710
	11th to 20th	Night	13% 6% 2 5% 3 3 3 3 5% 9% 48%	1625
	21st to end	Night	9% 7% 3 4 4 4 4 4 6% 9% 46%	1745
June	1st to 10th	Night	5% 3 1 3 4 5% 4 4 6% 9% 57%	1476
	11th to 20th	Night	5% 3 1 4 4 5% 5% 4 8% 10% 52%	1440
	21st to end	Night	5% 3 1 3 3 2 3 4 5% 9% 61%	1541
July	1st to 10th	Night	6% 3 1 4 4 4 4 4 7% 10% 53%	1620
	11th to 20th	Night	1 2 1 3 4 3 4 4 7% 11% 60%	1620
	21st to end	Night	7% 3 2 5% 4 3 5% 4 6% 10% 51%	1772
August	1st to 10th	Night	4 2 1 4 3 4 4 5% 9% 11% 53%	1611
	11th to 20th	Night	6% 3 1 5% 4 4 3 3 6% 8% 59%	1600
	21st to end	Night	6% 4 2 4 3 3 3 3 5% 7% 61%	1898
September	1st to 10th	Night	11% 5% 1 5% 3 3 3 3 4 6% 55%	1824
	11th to 20th	Night	8% 4 1 4 3 4 4 5% 5% 7% 55%	1980
	21st to end	Night	6% 4 2 5% 4 3 4 3 4 6% 60%	1980
October	1st to 10th	Night	11% 5% 1 4 3 3 4 3 5% 5% 55%	2128
	11th to 20th	Night	13% 5% 1 4 2 3 2 2 4 6% 57%	2160
	21st to end	Night	14% 7% 2 5% 3 3 3 2 3 4 52%	2376
November	1st to 10th	Night	8% 5% 1 4 3 2 3 2 4 6% 61%	2253
	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	48% 7% 10% 20% 14% 1	2470
	11th to 20th	Day	42% 8% 13% 23% 14%	2346
	21st to end	Day	46% 8% 14% 21% 9% 2	2531
June	1st to 10th	Day	27% 9% 17% 30% 16% 1	2479
	11th to 20th	Day	30% 9% 14% 29% 18% 2	2520
	21st to end	Day	27% 7% 15% 30% 17% 3	2410
July	1st to 10th	Day	32% 9% 16% 25% 16% 3	2276
	11th to 20th	Day	25% 8% 16% 28% 19% 4	2271
	21st to end	Day	30% 7% 15% 30% 16% 1	2405
August	1st to 10th	Day	32% 9% 17% 27% 13% 2	2314
	11th to 20th	Day	30% 6% 11% 33% 18% 2	2301
	21st to end	Day	29% 7% 12% 26% 20% 7%	2458
September	1st to 10th	Day	32% 6% 12% 26% 18% 6%	2133
	11th to 20th	Day	33% 7% 11% 26% 21% 3	1980
	21st to end	Day	29% 6% 10% 28% 24% 3	1980
October	1st to 10th	Day	33% 5% 11% 29% 20% 3	1814
	11th to 20th	Day	32% 4 7% 27% 25% 5%	1800
	21st to end	Day	37% 4 12% 22% 19% 5%	1980
November	1st to 10th	Day	29% 5% 13% 29% 19% 5%	1820
	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	41% 8% 13% 21% 15% 2	1710
	11th to 20th	Night	34% 6% 15% 27% 18% 1	1626
	21st to end	Night	33% 8% 18% 27% 11% 2	1746
June	1st to 10th	Night	22% 9% 18% 33% 15% 3	1476
	11th to 20th	Night	25% 9% 14% 32% 19% 3	1440
	21st to end	Night	18% 6% 15% 35% 21% 4	1541
July	1st to 10th	Night	25% 8% 15% 31% 16% 4	1575
	11th to 20th	Night	16% 7% 16% 33% 23% 4	1566
	21st to end	Night	27% 6% 13% 32% 21% 1	1673
August	1st to 10th	Night	20% 10% 18% 34% 14% 3	1601
	11th to 20th	Night	25% 6% 12% 32% 22% 3	1600
	21st to end	Night	23% 5% 12% 29% 24% 7%	1898
September	1st to 10th	Night	30% 6% 10% 28% 19% 8%	1824
	11th to 20th	Night	27% 6% 11% 25% 26% 5%	1980
	21st to end	Night	26% 6% 8% 26% 29% 5%	1980
October	1st to 10th	Night	30% 6% 8% 25% 25% 6%	2128
	11th to 20th	Night	31% 3 8% 28% 23% 8%	2160
	21st to end	Night	38% 3 8% 22% 25% 4	2376
November	1st to 10th	Night	26% 3 13% 27% 24% 6%	2253
	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	20% 9% 28% 30% 12% 2	641
	21st to end	Day	16% 8% 29% 26% 17% 4	679
June	1st to 10th	Day	5% 4 20% 36% 27% 7%	630
	11th to 20th	Day	7% 3 25% 39% 20% 5%	630
	21st to end	Day	7% 6% 31% 38% 16% 2	630
July	1st to 10th	Day	9% 4 13% 31% 33% 11%	621
	11th to 20th	Day	4 2 18% 35% 31% 10%	618
	21st to end	Day	9% 2 15% 35% 31% 8%	684
August	1st to 10th	Day	6% 2 16% 40% 30% 6%	626
	11th to 20th	Day	8% 3 14% 40% 28% 7%	615
	21st to end	Day	8% 1 15% 31% 35% 9%	577
September	1st to 10th	Day	13% 2 18% 34% 27% 6%	423
	11th to 20th	Day	5% 3 23% 36% 27% 6%	270
	21st to end	Day	13% 6% 26% 35% 16% 4	270
October	1st to 10th	Day	16% 7% 27% 25% 17% 7%	270
	11th to 20th	Day	11% 18% 41% 20% 9% 1	270
	21st to end	Day	23% 14% 35% 18% 9% 1	297
November	1st to 10th	Day	13% 11% 38% 25% 9% 4	270
	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% 31% 35% 13%	542
	21st to end	Night	11% 6% 29% 35% 17% 2	584
June	1st to 10th	Night	5% 4 22% 43% 26% 1	540
	11th to 20th	Night	6% 3 27% 44% 18% 2	540
	21st to end	Night	5% 4 28% 48% 14% 1	540
July	1st to 10th	Night	8% 2 12% 44% 32% 3	525
	11th to 20th	Night	2 1 15% 50% 30% 2	522
	21st to end	Night	8% 1 14% 49% 27% 1	591
August	1st to 10th	Night	4 2 15% 49% 29% 1	537
	11th to 20th	Night	7% 2 13% 45% 31% 3	534
	21st to end	Night	7% 1 13% 41% 36% 2	594
September	1st to 10th	Night	14% 3 19% 41% 22% 2	540
	11th to 20th	Night	9% 3 22% 40% 24% 3	540
	21st to end	Night	7% 4 25% 43% 19% 2	540
October	1st to 10th	Night	13% 4 28% 32% 21% 1	688
	11th to 20th	Night	15% 9% 38% 30% 8%	720
	21st to end	Night	19% 11% 35% 27% 8%	792
November	1st to 10th	Night	10% 10% 33% 34% 11% 1	773
	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 2024-05-11 04:13:34. Version ac07

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