Lincoln
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lincoln clear sky chart from 2005-11-06 to 2024-11-04.

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	11% 7% 3 7% 4 4 4 4 5% 7% 45%	100982
	Night	10% 7% 2 6% 4 3 4 3 5% 7% 49%	98111
Transparency	Day	37% 6% 13% 25% 17% 2	104671
	Night	34% 5% 13% 26% 19% 3	102549
Seeing	Day	14% 9% 31% 29% 14% 3	15778
	Night	13% 9% 34% 33% 10% 1	25623

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	11% 13% 5% 11% 8% 6% 5% 3 4 5% 28%	2847
	11th to 20th	Day	9% 12% 5% 9% 4 6% 6% 4 5% 5% 37%	2850
	21st to end	Day	8% 13% 6% 13% 5% 4 3 3 4 5% 35%	3135
February	1st to 10th	Day	10% 11% 5% 8% 6% 4 4 4 6% 6% 36%	1710
	11th to 20th	Day	9% 10% 3 7% 4 4 4 3 6% 6% 43%	1735
	21st to end	Day	10% 7% 4 6% 5% 4 4 3 5% 7% 46%	1570
March	1st to 10th	Day	11% 9% 3 6% 3 3 3 2 3 5% 52%	3363
	11th to 20th	Day	11% 8% 2 6% 3 3 3 3 4 5% 50%	3480
	21st to end	Day	19% 11% 3 8% 5% 4 4 4 6% 6% 31%	3814
April	1st to 10th	Day	15% 8% 3 5% 4 4 3 3 5% 6% 46%	2117
	11th to 20th	Day	15% 8% 2 6% 4 4 4 3 5% 7% 41%	2392
	21st to end	Day	19% 7% 3 6% 3 4 4 4 5% 7% 39%	2470
May	1st to 10th	Day	16% 8% 2 6% 4 4 5% 4 5% 8% 38%	4082
	11th to 20th	Day	14% 7% 3 6% 5% 4 4 3 5% 6% 45%	4082
	21st to end	Day	14% 6% 2 7% 4 4 5% 4 6% 7% 40%	4477
June	1st to 10th	Day	7% 4 2 5% 4 4 4 4 6% 9% 51%	2603
	11th to 20th	Day	8% 6% 2 4 4 4 4 5% 6% 9% 47%	2660
	21st to end	Day	7% 5% 1 5% 5% 5% 5% 4 6% 8% 48%	2548
July	1st to 10th	Day	11% 6% 2 6% 4 4 4 4 6% 8% 44%	4120
	11th to 20th	Day	7% 4 2 6% 4 4 4 4 6% 8% 53%	4120
	21st to end	Day	4 3 1 5% 4 4 4 5% 8% 10% 53%	4465
August	1st to 10th	Day	7% 5% 2 5% 4 5% 6% 5% 7% 10% 45%	4104
	11th to 20th	Day	11% 6% 2 7% 4 4 5% 4 7% 7% 43%	4041
	21st to end	Day	6% 4 2 5% 4 4 5% 4 6% 8% 52%	4482
September	1st to 10th	Day	13% 4 2 4 2 3 3 4 5% 6% 54%	2161
	11th to 20th	Day	9% 5% 1 5% 3 4 4 3 4 6% 55%	2090
	21st to end	Day	10% 4 1 5% 3 3 3 2 5% 6% 58%	2090
October	1st to 10th	Day	13% 7% 2 4 3 3 3 3 3 5% 54%	1971
	11th to 20th	Day	11% 5% 2 5% 3 2 3 3 3 4 58%	1900
	21st to end	Day	13% 8% 2 5% 3 4 3 2 4 7% 49%	2090
November	1st to 10th	Day	9% 6% 2 5% 3 3 3 3 5% 6% 55%	1700
	11th to 20th	Day	9% 6% 2 6% 4 4 4 3 5% 6% 51%	1710
	21st to end	Day	13% 9% 3 4 3 3 4 3 5% 7% 45%	1544
December	1st to 10th	Day	9% 7% 3 6% 5% 5% 4 3 6% 6% 47%	1520
	11th to 20th	Day	8% 10% 3 8% 5% 4 4 3 6% 8% 41%	1918
	21st to end	Day	15% 12% 5% 14% 5% 5% 4 3 4 5% 28%	3021
January	1st to 10th	Night	8% 10% 4 15% 6% 5% 4 3 6% 5% 32%	4108
	11th to 20th	Night	9% 9% 3 7% 4 6% 7% 4 5% 5% 41%	4120
	21st to end	Night	12% 12% 6% 11% 4 2 3 3 4 5% 39%	4532
February	1st to 10th	Night	11% 11% 4 7% 5% 5% 5% 3 5% 5% 40%	2470
	11th to 20th	Night	9% 8% 2 7% 6% 5% 4 4 6% 7% 43%	2346
	21st to end	Night	9% 8% 3 6% 4 3 4 3 4 7% 49%	1884
March	1st to 10th	Night	11% 6% 2 5% 3 3 3 3 4 5% 54%	3493
	11th to 20th	Night	11% 6% 2 5% 3 2 2 3 4 5% 57%	3480
	21st to end	Night	19% 9% 2 7% 5% 4 4 3 5% 6% 35%	3817
April	1st to 10th	Night	12% 8% 2 5% 4 3 3 3 5% 7% 48%	2062
	11th to 20th	Night	10% 8% 2 6% 4 3 3 3 5% 8% 47%	1736
	21st to end	Night	16% 7% 2 6% 3 4 4 3 4 7% 45%	1710
May	1st to 10th	Night	19% 6% 2 4 3 3 3 3 5% 7% 44%	2823
	11th to 20th	Night	11% 6% 2 5% 4 3 4 3 5% 7% 51%	2823
	21st to end	Night	15% 7% 2 6% 3 3 4 3 5% 7% 45%	3090
June	1st to 10th	Night	5% 3 2 4 5% 4 4 3 7% 10% 54%	1572
	11th to 20th	Night	7% 4 2 4 4 3 4 4 7% 9% 52%	1520
	21st to end	Night	4 3 1 4 3 3 4 4 7% 8% 58%	1622
July	1st to 10th	Night	8% 6% 2 6% 3 4 3 3 6% 8% 51%	2850
	11th to 20th	Night	4 3 1 3 2 4 4 3 6% 9% 60%	2850
	21st to end	Night	3 2 1 3 3 3 4 4 7% 10% 60%	3098
August	1st to 10th	Night	3 3 2 4 4 3 4 3 6% 10% 59%	2836
	11th to 20th	Night	11% 5% 2 5% 3 3 4 4 5% 8% 50%	2798
	21st to end	Night	6% 5% 1 4 3 4 3 3 6% 8% 57%	3183
September	1st to 10th	Night	8% 4 2 4 2 2 3 2 5% 7% 61%	2015
	11th to 20th	Night	8% 3 1 4 3 2 4 3 4 7% 59%	2090
	21st to end	Night	9% 4 2 4 2 3 3 3 4 5% 60%	2090
October	1st to 10th	Night	12% 6% 2 4 3 4 3 3 4 6% 52%	2190
	11th to 20th	Night	12% 5% 2 4 3 2 2 2 4 4 59%	2280
	21st to end	Night	13% 6% 2 5% 2 2 3 3 4 5% 54%	2508
November	1st to 10th	Night	7% 4 2 4 3 3 3 3 5% 6% 59%	2446
	11th to 20th	Night	9% 6% 2 6% 4 3 3 3 5% 6% 54%	2470
	21st to end	Night	11% 8% 2 4 3 2 3 3 4 6% 53%	2632
December	1st to 10th	Night	8% 7% 3 7% 5% 3 4 3 5% 6% 49%	2660
	11th to 20th	Night	9% 8% 3 7% 3 3 3 3 5% 6% 51%	3279
	21st to end	Night	18% 13% 5% 11% 4 3 3 2 4 4 34%	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	56% 6% 13% 17% 8% 1	2848
	11th to 20th	Day	47% 6% 17% 18% 11% 1	2850
	21st to end	Day	50% 6% 12% 18% 12%	3135
February	1st to 10th	Day	47% 6% 16% 20% 10% 1	1710
	11th to 20th	Day	41% 5% 13% 23% 15% 3	1744
	21st to end	Day	38% 6% 13% 24% 16% 3	1570
March	1st to 10th	Day	37% 5% 9% 27% 20% 3	3363
	11th to 20th	Day	35% 6% 11% 27% 19% 1	3480
	21st to end	Day	50% 9% 21% 15% 4 1	3814
April	1st to 10th	Day	39% 5% 13% 25% 16% 2	2117
	11th to 20th	Day	42% 5% 13% 23% 14% 3	2392
	21st to end	Day	44% 7% 11% 26% 13%	2470
May	1st to 10th	Day	41% 8% 13% 23% 13% 3	4120
	11th to 20th	Day	40% 6% 11% 23% 19% 1	4086
	21st to end	Day	39% 8% 13% 25% 13% 1	4489
June	1st to 10th	Day	28% 8% 18% 32% 13% 2	2603
	11th to 20th	Day	32% 8% 14% 29% 16% 2	2660
	21st to end	Day	31% 9% 14% 29% 14% 4	2548
July	1st to 10th	Day	37% 5% 14% 27% 16% 1	4056
	11th to 20th	Day	30% 5% 13% 32% 18% 3	4051
	21st to end	Day	24% 6% 17% 28% 21% 4	4325
August	1st to 10th	Day	32% 8% 16% 26% 16% 3	4090
	11th to 20th	Day	38% 6% 16% 23% 17% 1	4080
	21st to end	Day	30% 5% 16% 25% 19% 6%	4481
September	1st to 10th	Day	30% 5% 11% 28% 20% 5%	2161
	11th to 20th	Day	30% 5% 12% 29% 22% 2	2090
	21st to end	Day	28% 4 9% 32% 25% 2	2090
October	1st to 10th	Day	21% 4 6% 19% 46% 4	3270
	11th to 20th	Day	21% 3 11% 30% 27% 8%	3140
	21st to end	Day	33% 3 11% 28% 22% 3	3428
November	1st to 10th	Day	29% 4 14% 28% 21% 3	1700
	11th to 20th	Day	34% 6% 13% 26% 20% 2	1710
	21st to end	Day	39% 4 11% 29% 15% 2	1544
December	1st to 10th	Day	36% 5% 16% 27% 14% 2	1520
	11th to 20th	Day	41% 6% 16% 29% 9%	1915
	21st to end	Day	58% 6% 9% 18% 8%	3021
January	1st to 10th	Night	49% 6% 13% 18% 12%	4108
	11th to 20th	Night	42% 5% 15% 25% 12% 1	4120
	21st to end	Night	48% 4 14% 20% 14% 1	4532
February	1st to 10th	Night	46% 6% 13% 19% 13% 3	2470
	11th to 20th	Night	39% 6% 14% 24% 15% 3	2347
	21st to end	Night	34% 5% 11% 24% 21% 6%	1884
March	1st to 10th	Night	31% 6% 10% 26% 25% 3	3493
	11th to 20th	Night	30% 4 9% 27% 24% 5%	3480
	21st to end	Night	47% 7% 21% 18% 6% 1	3817
April	1st to 10th	Night	36% 5% 11% 26% 18% 3	2062
	11th to 20th	Night	35% 6% 13% 26% 18% 3	1736
	21st to end	Night	39% 6% 11% 25% 18% 1	1710
May	1st to 10th	Night	39% 6% 12% 23% 17% 2	2850
	11th to 20th	Night	33% 6% 13% 25% 22% 1	2824
	21st to end	Night	37% 7% 14% 20% 19% 2	3099
June	1st to 10th	Night	25% 9% 16% 31% 18% 2	1572
	11th to 20th	Night	26% 7% 16% 28% 18% 5%	1520
	21st to end	Night	22% 7% 15% 33% 21% 3	1622
July	1st to 10th	Night	31% 5% 12% 30% 18% 3	2805
	11th to 20th	Night	22% 5% 14% 33% 23% 3	2796
	21st to end	Night	16% 7% 18% 31% 26% 2	2999
August	1st to 10th	Night	22% 6% 17% 31% 21% 3	2826
	11th to 20th	Night	33% 4 16% 29% 16% 1	2825
	21st to end	Night	26% 4 16% 28% 17% 9%	3183
September	1st to 10th	Night	24% 4 12% 28% 23% 8%	2015
	11th to 20th	Night	24% 5% 11% 33% 23% 4	2090
	21st to end	Night	26% 4 8% 28% 30% 4	2090
October	1st to 10th	Night	21% 4 7% 16% 46% 7%	3658
	11th to 20th	Night	22% 2 8% 31% 28% 9%	3779
	21st to end	Night	31% 3 9% 31% 24% 2	4120
November	1st to 10th	Night	25% 6% 13% 27% 25% 5%	2446
	11th to 20th	Night	32% 4 11% 30% 20% 3	2470
	21st to end	Night	34% 4 12% 26% 21% 3	2632
December	1st to 10th	Night	35% 5% 14% 29% 15% 1	2660
	11th to 20th	Night	34% 5% 13% 35% 13% 1	3281
	21st to end	Night	54% 5% 9% 22% 8% 1	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	17% 16% 38% 20% 7% 1	270
	11th to 20th	Day	21% 14% 37% 21% 7%	270
	21st to end	Day	14% 12% 42% 22% 9%	297
February	1st to 10th	Day	15% 19% 43% 19% 3	270
	11th to 20th	Day	16% 14% 38% 24% 7%	270
	21st to end	Day	11% 20% 43% 20% 5%	225
March	1st to 10th	Day	17% 13% 42% 23% 4 1	270
	11th to 20th	Day	24% 13% 36% 19% 6% 1	270
	21st to end	Day	29% 17% 36% 15% 3	297
April	1st to 10th	Day	19% 20% 39% 18% 3	297
	11th to 20th	Day	19% 16% 37% 21% 7%	590
	21st to end	Day	22% 15% 32% 20% 8% 2	650
May	1st to 10th	Day	19% 13% 34% 25% 8% 1	653
	11th to 20th	Day	19% 9% 33% 25% 12% 2	675
	21st to end	Day	16% 8% 32% 29% 13% 2	734
June	1st to 10th	Day	5% 6% 22% 39% 23% 5%	680
	11th to 20th	Day	9% 7% 31% 33% 16% 4	680
	21st to end	Day	8% 6% 34% 36% 14% 2	680
July	1st to 10th	Day	10% 4 19% 35% 25% 7%	671
	11th to 20th	Day	6% 3 22% 40% 21% 8%	668
	21st to end	Day	7% 2 17% 41% 28% 4	739
August	1st to 10th	Day	7% 2 23% 40% 23% 5%	676
	11th to 20th	Day	9% 4 19% 43% 22% 3	665
	21st to end	Day	10% 3 21% 34% 26% 5%	724
September	1st to 10th	Day	13% 4 24% 36% 20% 3	371
	11th to 20th	Day	6% 6% 27% 36% 21% 4	300
	21st to end	Day	12% 9% 31% 28% 16% 4	300
October	1st to 10th	Day	22% 7% 24% 27% 15% 6%	300
	11th to 20th	Day	10% 15% 41% 24% 9% 1	300
	21st to end	Day	16% 15% 39% 20% 9% 1	330
November	1st to 10th	Day	15% 15% 38% 23% 7% 3	279
	11th to 20th	Day	12% 16% 43% 22% 7%	270
	21st to end	Day	21% 11% 32% 26% 9%	270
December	1st to 10th	Day	8% 14% 41% 29% 7% 1	270
	11th to 20th	Day	17% 11% 38% 26% 8%	270
	21st to end	Day	18% 17% 43% 20% 2	297
January	1st to 10th	Night	12% 12% 38% 30% 7%	950
	11th to 20th	Night	14% 12% 39% 28% 6%	950
	21st to end	Night	14% 9% 41% 30% 5%	1045
February	1st to 10th	Night	16% 10% 42% 27% 4	950
	11th to 20th	Night	12% 13% 41% 30% 4	872
	21st to end	Night	13% 14% 43% 24% 5%	628
March	1st to 10th	Night	13% 14% 39% 27% 6%	622
	11th to 20th	Night	18% 9% 40% 27% 5%	570
	21st to end	Night	22% 11% 39% 23% 5%	627
April	1st to 10th	Night	16% 14% 42% 22% 5%	570
	11th to 20th	Night	14% 15% 40% 27% 4 1	563
	21st to end	Night	19% 12% 35% 26% 8% 1	570
May	1st to 10th	Night	18% 8% 35% 29% 10%	570
	11th to 20th	Night	14% 9% 33% 35% 8% 1	561
	21st to end	Night	15% 10% 30% 32% 12% 1	617
June	1st to 10th	Night	5% 5% 27% 46% 17%	570
	11th to 20th	Night	7% 4 33% 42% 13%	570
	21st to end	Night	4 5% 36% 42% 13%	570
July	1st to 10th	Night	8% 3 17% 42% 30% 1	555
	11th to 20th	Night	3 1 19% 52% 24% 1	552
	21st to end	Night	3 1 16% 54% 25% 1	624
August	1st to 10th	Night	5% 2 18% 51% 21% 2	567
	11th to 20th	Night	7% 2 20% 49% 21% 1	564
	21st to end	Night	9% 2 23% 40% 24% 3	627
September	1st to 10th	Night	9% 2 28% 41% 19% 1	570
	11th to 20th	Night	9% 2 30% 43% 15% 1	570
	21st to end	Night	11% 5% 34% 34% 16% 1	570
October	1st to 10th	Night	15% 7% 31% 33% 12% 2	670
	11th to 20th	Night	15% 9% 39% 30% 7%	760
	21st to end	Night	17% 12% 32% 30% 9%	836
November	1st to 10th	Night	9% 11% 36% 35% 9%	938
	11th to 20th	Night	13% 11% 41% 29% 7%	950
	21st to end	Night	14% 13% 36% 28% 9% 1	950
December	1st to 10th	Night	13% 12% 41% 29% 6% 1	950
	11th to 20th	Night	15% 11% 34% 33% 7%	950
	21st to end	Night	19% 12% 37% 28% 5%	1045

Page generated at 2024-11-01 21:47:30. Version ac07

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