Laramie
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Laramie clear sky chart from 2005-11-06 to 2024-11-05.

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	4 6% 2 6% 4 4 5% 4 6% 8% 50%	105286
	Night	3 6% 2 6% 4 4 4 4 6% 8% 55%	102464
Transparency	Day	29% 8% 12% 23% 19% 8%	105029
	Night	26% 7% 14% 28% 20% 6%	102310
Seeing	Day	10% 22% 33% 23% 11% 2	15699
	Night	7% 22% 36% 26% 9% 1	25702

By Month

Percentage Cloud Cover SW (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	4 4 8% 8% 4 4 3 5% 6% 52%	2538
	11th to 20th	Day	9% 4 11% 7% 6% 6% 4 6% 7% 41%	2553
	21st to end	Day	1 4 3 7% 3 4 5% 3 5% 7% 58%	3146
February	1st to 10th	Day	2 8% 3 9% 7% 5% 4 4 5% 8% 44%	1710
	11th to 20th	Day	1 8% 3 9% 4 5% 4 3 7% 9% 46%	1762
	21st to end	Day	1 7% 4 7% 4 4 4 4 7% 8% 51%	1570
March	1st to 10th	Day	2 8% 4 9% 4 4 4 4 6% 7% 50%	3130
	11th to 20th	Day	3 10% 4 7% 4 4 4 4 6% 8% 46%	3486
	21st to end	Day	3 10% 4 10% 6% 5% 5% 4 6% 7% 39%	4030
April	1st to 10th	Day	4 11% 3 6% 4 4 4 5% 6% 7% 45%	2280
	11th to 20th	Day	7% 13% 4 8% 5% 5% 5% 4 6% 7% 37%	2251
	21st to end	Day	7% 11% 3 7% 5% 5% 5% 4 7% 7% 39%	2280
May	1st to 10th	Day	7% 15% 4 9% 6% 4 5% 4 6% 6% 34%	4211
	11th to 20th	Day	7% 7% 2 7% 5% 6% 6% 5% 7% 8% 40%	4388
	21st to end	Day	6% 7% 3 6% 5% 5% 6% 5% 7% 8% 44%	4825
June	1st to 10th	Day	5% 5% 1 5% 5% 4 6% 5% 8% 9% 45%	2660
	11th to 20th	Day	6% 4 2 4 4 4 5% 5% 7% 8% 50%	2660
	21st to end	Day	3 3 2 5% 4 4 5% 5% 8% 9% 52%	2660
July	1st to 10th	Day	4 4 1 4 4 5% 5% 5% 7% 8% 54%	4430
	11th to 20th	Day	2 3 1 5% 4 6% 6% 5% 8% 9% 50%	4430
	21st to end	Day	4 4 2 6% 5% 5% 6% 4 7% 9% 50%	4778
August	1st to 10th	Day	3 4 2 6% 5% 6% 6% 6% 8% 10% 44%	4092
	11th to 20th	Day	4 4 2 6% 5% 6% 6% 5% 7% 9% 48%	3831
	21st to end	Day	4 3 1 5% 3 4 5% 4 7% 8% 56%	4180
September	1st to 10th	Day	5% 4 1 5% 3 4 5% 4 4 7% 58%	2280
	11th to 20th	Day	4 4 1 5% 4 3 4 4 5% 6% 60%	2280
	21st to end	Day	5% 5% 1 5% 3 3 3 2 4 6% 63%	2062
October	1st to 10th	Day	4 4 1 3 2 2 3 2 3 4 72%	3170
	11th to 20th	Day	3 5% 2 7% 4 4 4 3 5% 6% 57%	3150
	21st to end	Day	4 9% 3 5% 3 2 3 3 4 6% 59%	3298
November	1st to 10th	Day	3 6% 2 4 2 4 3 3 5% 8% 60%	1709
	11th to 20th	Day	2 8% 2 5% 3 3 3 3 6% 7% 57%	1696
	21st to end	Day	2 6% 3 7% 4 3 4 3 6% 6% 55%	1520
December	1st to 10th	Day	1 6% 4 8% 6% 4 4 4 6% 8% 50%	1520
	11th to 20th	Day	1 7% 3 5% 4 3 3 4 6% 11% 54%	1926
	21st to end	Day	1 10% 4 9% 5% 4 4 3 6% 7% 49%	2794
January	1st to 10th	Night	6% 4 10% 5% 4 4 3 5% 7% 51%	4417
	11th to 20th	Night	1 7% 4 11% 4 4 4 4 5% 9% 48%	4430
	21st to end	Night	1 6% 3 6% 4 4 5% 4 5% 7% 56%	4525
February	1st to 10th	Night	1 7% 4 9% 5% 4 4 4 5% 7% 51%	2470
	11th to 20th	Night	2 8% 3 7% 5% 5% 4 3 5% 7% 50%	2304
	21st to end	Night	1 7% 4 8% 4 3 3 3 4 7% 57%	1884
March	1st to 10th	Night	1 6% 3 8% 4 4 4 4 6% 7% 53%	3734
	11th to 20th	Night	2 9% 3 7% 4 4 4 3 5% 7% 53%	3490
	21st to end	Night	4 10% 3 8% 5% 5% 4 3 6% 7% 45%	3615
April	1st to 10th	Night	4 8% 3 6% 4 4 4 4 6% 7% 51%	1900
	11th to 20th	Night	6% 11% 3 6% 4 4 4 4 5% 7% 46%	1877
	21st to end	Night	7% 11% 3 6% 3 3 3 4 5% 7% 48%	1900
May	1st to 10th	Night	6% 11% 3 6% 4 4 5% 3 6% 7% 47%	2756
	11th to 20th	Night	7% 6% 2 6% 4 4 4 5% 6% 10% 46%	2517
	21st to end	Night	5% 6% 2 4 3 4 4 4 7% 7% 53%	2762
June	1st to 10th	Night	3 3 1 3 3 4 4 4 7% 11% 57%	1520
	11th to 20th	Night	4 2 1 4 4 3 4 4 6% 8% 61%	1520
	21st to end	Night	3 4 1 4 3 3 4 3 6% 8% 62%	1520
July	1st to 10th	Night	3 3 1 4 4 4 5% 4 6% 8% 57%	2540
	11th to 20th	Night	2 2 1 4 4 3 5% 5% 7% 10% 56%	2540
	21st to end	Night	2 2 1 4 3 4 5% 4 7% 9% 59%	2782
August	1st to 10th	Night	3 3 1 4 4 4 5% 5% 7% 11% 53%	2847
	11th to 20th	Night	3 3 2 6% 4 5% 5% 5% 7% 10% 52%	2996
	21st to end	Night	3 3 1 4 3 3 4 4 6% 10% 58%	3487
September	1st to 10th	Night	5% 4 2 3 3 3 4 3 5% 7% 61%	1900
	11th to 20th	Night	3 3 2 4 3 3 4 2 5% 7% 65%	1900
	21st to end	Night	5% 4 1 3 3 3 4 2 5% 7% 65%	2113
October	1st to 10th	Night	3 3 1 2 2 2 2 2 3 4 75%	3800
	11th to 20th	Night	4 4 2 5% 3 3 3 3 5% 8% 60%	3778
	21st to end	Night	4 6% 2 4 2 2 3 2 4 8% 63%	4227
November	1st to 10th	Night	3 6% 2 4 2 3 4 3 5% 8% 61%	2470
	11th to 20th	Night	3 7% 3 5% 3 3 3 3 5% 6% 59%	2479
	21st to end	Night	2 7% 3 6% 3 3 3 4 6% 8% 55%	2660
December	1st to 10th	Night	1 6% 3 7% 3 4 3 3 5% 8% 57%	2660
	11th to 20th	Night	2 6% 3 5% 4 2 4 3 6% 10% 55%	3271
	21st to end	Night	2 11% 3 7% 5% 4 4 3 6% 8% 47%	4873

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	28% 11% 16% 21% 21% 2	2539
	11th to 20th	Day	33% 16% 20% 18% 12% 2	2553
	21st to end	Day	22% 8% 22% 30% 15% 3	3146
February	1st to 10th	Day	36% 7% 18% 21% 15% 2	1710
	11th to 20th	Day	32% 8% 14% 28% 15% 4	1771
	21st to end	Day	28% 7% 17% 26% 19% 3	1570
March	1st to 10th	Day	27% 8% 12% 32% 17% 3	3130
	11th to 20th	Day	30% 12% 16% 31% 10% 2	3486
	21st to end	Day	37% 10% 15% 30% 6% 2	4030
April	1st to 10th	Day	34% 8% 16% 22% 16% 5%	2280
	11th to 20th	Day	42% 9% 11% 21% 14% 2	2254
	21st to end	Day	41% 10% 9% 25% 15% 1	2280
May	1st to 10th	Day	46% 8% 10% 16% 15% 5%	4211
	11th to 20th	Day	34% 12% 11% 26% 14% 2	4392
	21st to end	Day	31% 10% 10% 24% 20% 5%	4825
June	1st to 10th	Day	29% 10% 16% 22% 18% 6%	2660
	11th to 20th	Day	27% 9% 10% 17% 24% 12%	2660
	21st to end	Day	23% 9% 9% 22% 23% 14%	2660
July	1st to 10th	Day	24% 8% 6% 15% 26% 21%	4361
	11th to 20th	Day	25% 6% 8% 19% 22% 19%	4355
	21st to end	Day	28% 7% 7% 17% 21% 20%	4627
August	1st to 10th	Day	31% 6% 12% 24% 15% 12%	4078
	11th to 20th	Day	31% 5% 10% 16% 25% 12%	3869
	21st to end	Day	25% 4 10% 18% 26% 16%	4179
September	1st to 10th	Day	24% 5% 8% 18% 29% 16%	2280
	11th to 20th	Day	22% 6% 9% 22% 28% 13%	2280
	21st to end	Day	23% 5% 7% 23% 35% 7%	2062
October	1st to 10th	Day	18% 4 5% 19% 29% 25%	3170
	11th to 20th	Day	28% 4 8% 35% 20% 6%	3150
	21st to end	Day	28% 3 7% 34% 24% 3	3298
November	1st to 10th	Day	22% 7% 15% 28% 27% 3	1709
	11th to 20th	Day	24% 6% 16% 30% 21% 3	1696
	21st to end	Day	26% 7% 13% 31% 20% 3	1520
December	1st to 10th	Day	31% 7% 22% 23% 15% 2	1520
	11th to 20th	Day	24% 10% 16% 35% 14% 1	1924
	21st to end	Day	34% 7% 13% 24% 16% 6%	2794
January	1st to 10th	Night	30% 8% 15% 31% 14% 3	4417
	11th to 20th	Night	27% 12% 20% 20% 15% 5%	4430
	21st to end	Night	26% 9% 22% 28% 12% 4	4525
February	1st to 10th	Night	32% 6% 19% 27% 14% 2	2470
	11th to 20th	Night	33% 6% 14% 29% 16% 3	2305
	21st to end	Night	28% 5% 15% 25% 22% 5%	1884
March	1st to 10th	Night	25% 9% 11% 33% 19% 3	3734
	11th to 20th	Night	29% 8% 14% 33% 14% 2	3490
	21st to end	Night	33% 9% 15% 34% 8% 1	3615
April	1st to 10th	Night	29% 8% 15% 26% 16% 5%	1900
	11th to 20th	Night	35% 7% 12% 27% 16% 3	1877
	21st to end	Night	36% 7% 10% 29% 18%	1900
May	1st to 10th	Night	35% 8% 9% 23% 20% 4	2756
	11th to 20th	Night	29% 11% 15% 31% 10% 3	2518
	21st to end	Night	25% 9% 14% 28% 23% 2	2762
June	1st to 10th	Night	19% 10% 22% 27% 17% 5%	1520
	11th to 20th	Night	21% 6% 13% 25% 24% 13%	1520
	21st to end	Night	20% 6% 9% 25% 25% 15%	1520
July	1st to 10th	Night	22% 7% 8% 21% 26% 15%	2500
	11th to 20th	Night	21% 6% 10% 29% 21% 14%	2492
	21st to end	Night	20% 6% 11% 26% 22% 15%	2695
August	1st to 10th	Night	24% 5% 18% 26% 19% 7%	2838
	11th to 20th	Night	28% 4 16% 22% 18% 12%	3023
	21st to end	Night	21% 5% 13% 20% 30% 12%	3487
September	1st to 10th	Night	22% 6% 9% 21% 26% 16%	1900
	11th to 20th	Night	20% 6% 9% 26% 28% 12%	1900
	21st to end	Night	19% 6% 9% 25% 34% 8%	2113
October	1st to 10th	Night	14% 4 6% 19% 37% 20%	3800
	11th to 20th	Night	23% 4 11% 32% 24% 5%	3778
	21st to end	Night	22% 4 10% 36% 23% 5%	4227
November	1st to 10th	Night	22% 6% 15% 28% 25% 5%	2470
	11th to 20th	Night	24% 6% 15% 32% 19% 5%	2479
	21st to end	Night	26% 6% 13% 32% 20% 4	2660
December	1st to 10th	Night	25% 8% 21% 27% 17% 3	2660
	11th to 20th	Night	24% 8% 17% 35% 15% 1	3272
	21st to end	Night	32% 8% 13% 25% 17% 4	4873

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	11% 33% 31% 16% 7% 2	270
	11th to 20th	Day	10% 42% 30% 16% 3	270
	21st to end	Day	5% 38% 40% 13% 3	297
February	1st to 10th	Day	13% 46% 34% 6% 1	270
	11th to 20th	Day	11% 43% 36% 9% 1	270
	21st to end	Day	19% 37% 34% 9%	225
March	1st to 10th	Day	11% 38% 35% 13% 3	270
	11th to 20th	Day	12% 30% 37% 18% 2 1	456
	21st to end	Day	16% 31% 37% 13% 3	506
April	1st to 10th	Day	17% 34% 36% 11% 2	460
	11th to 20th	Day	19% 36% 30% 11% 3	452
	21st to end	Day	18% 25% 34% 17% 5% 1	460
May	1st to 10th	Day	19% 23% 30% 18% 8% 1	601
	11th to 20th	Day	16% 16% 31% 24% 12% 2	675
	21st to end	Day	11% 19% 27% 25% 14% 3	734
June	1st to 10th	Day	5% 15% 28% 30% 17% 4	680
	11th to 20th	Day	9% 14% 39% 26% 11% 1	680
	21st to end	Day	4 14% 35% 29% 18% 1	680
July	1st to 10th	Day	7% 6% 21% 36% 25% 4	671
	11th to 20th	Day	4 6% 28% 38% 21% 4	668
	21st to end	Day	4 5% 25% 35% 27% 4	727
August	1st to 10th	Day	9% 6% 37% 33% 13% 2	487
	11th to 20th	Day	6% 6% 32% 36% 15% 5%	477
	21st to end	Day	6% 9% 33% 31% 17% 4	539
September	1st to 10th	Day	7% 10% 32% 28% 18% 4	490
	11th to 20th	Day	5% 15% 38% 26% 13% 3	490
	21st to end	Day	8% 16% 31% 22% 17% 6%	305
October	1st to 10th	Day	9% 18% 29% 26% 13% 5%	300
	11th to 20th	Day	10% 29% 31% 21% 5% 5%	300
	21st to end	Day	9% 31% 39% 15% 4 1	330
November	1st to 10th	Day	7% 33% 39% 15% 4 2	282
	11th to 20th	Day	13% 32% 43% 10% 3	270
	21st to end	Day	11% 35% 39% 13% 2	270
December	1st to 10th	Day	13% 40% 36% 7% 5%	270
	11th to 20th	Day	12% 44% 34% 9%	270
	21st to end	Day	14% 44% 28% 10% 2 1	297
January	1st to 10th	Night	6% 37% 36% 14% 6% 1	950
	11th to 20th	Night	6% 43% 34% 11% 5%	950
	21st to end	Night	5% 32% 43% 16% 4	840
February	1st to 10th	Night	5% 38% 42% 10% 4	760
	11th to 20th	Night	6% 35% 39% 17% 3	744
	21st to end	Night	8% 37% 43% 11% 1	628
March	1st to 10th	Night	5% 30% 43% 18% 4 1	760
	11th to 20th	Night	8% 21% 41% 25% 5%	760
	21st to end	Night	10% 20% 44% 21% 5% 1	713
April	1st to 10th	Night	10% 22% 43% 22% 3	570
	11th to 20th	Night	13% 22% 39% 20% 5%	563
	21st to end	Night	15% 18% 33% 26% 8% 1	570
May	1st to 10th	Night	13% 16% 33% 28% 9% 1	570
	11th to 20th	Night	14% 8% 31% 34% 12% 1	561
	21st to end	Night	6% 11% 35% 31% 16% 1	617
June	1st to 10th	Night	5% 9% 30% 40% 16% 1	570
	11th to 20th	Night	7% 9% 39% 36% 9%	570
	21st to end	Night	4 7% 29% 42% 17%	570
July	1st to 10th	Night	4 3 25% 45% 22% 1	555
	11th to 20th	Night	3 1 23% 52% 20% 2	552
	21st to end	Night	3 2 21% 47% 25% 1	624
August	1st to 10th	Night	4 2 24% 50% 19% 1	567
	11th to 20th	Night	4 1 24% 50% 18% 2	564
	21st to end	Night	4 3 24% 42% 25% 1	627
September	1st to 10th	Night	8% 4 23% 45% 18% 2	570
	11th to 20th	Night	5% 5% 28% 44% 16% 2	570
	21st to end	Night	6% 8% 34% 35% 16% 1	598
October	1st to 10th	Night	7% 15% 34% 31% 12% 1	760
	11th to 20th	Night	7% 18% 36% 30% 8% 1	760
	21st to end	Night	10% 19% 44% 21% 5% 1	894
November	1st to 10th	Night	6% 25% 44% 20% 5% 1	950
	11th to 20th	Night	9% 34% 42% 14% 2	950
	21st to end	Night	7% 28% 45% 17% 3	950
December	1st to 10th	Night	7% 39% 37% 13% 3	950
	11th to 20th	Night	6% 38% 40% 14% 2	950
	21st to end	Night	7% 44% 33% 12% 4	1045

Page generated at 2024-11-03 00:11:17. Version ac07

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