Clovis
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Clovis clear sky chart from 2005-11-06 to 2026-07-31.

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	5% 3 1 4 3 3 3 3 5% 7% 63%	146676
	Night	5% 3 1 4 3 3 3 3 5% 7% 62%	143806
Transparency	Day	21% 4 8% 20% 27% 19%	141766
	Night	21% 4 8% 19% 28% 20%	139726
Seeing	Day	7% 9% 28% 33% 19% 4	17540
	Night	6% 9% 35% 37% 13% 1	27484

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	6% 7% 2 5% 3 3 3 3 5% 6% 57%	4720
	11th to 20th	Day	2 3 1 3 2 2 2 2 3 5% 76%	5238
	21st to end	Day	7% 5% 2 6% 4 3 3 3 5% 6% 57%	6443
February	1st to 10th	Day	3 5% 1 4 3 3 3 3 5% 6% 66%	2100
	11th to 20th	Day	5% 6% 2 5% 3 3 2 2 4 6% 61%	2049
	21st to end	Day	3 5% 2 4 2 2 3 3 4 5% 67%	1730
March	1st to 10th	Day	4 4 1 4 3 3 3 3 4 5% 66%	4600
	11th to 20th	Day	8% 4 1 4 3 3 3 3 5% 8% 59%	4784
	21st to end	Day	2 4 1 6% 4 4 4 4 6% 7% 59%	6101
April	1st to 10th	Day	4 3 1 3 3 2 3 3 4 6% 68%	2520
	11th to 20th	Day	6% 4 1 4 3 2 3 2 4 5% 66%	2491
	21st to end	Day	3 3 1 3 2 2 2 3 5% 7% 68%	2520
May	1st to 10th	Day	8% 3 1 4 3 3 3 3 4 6% 62%	7271
	11th to 20th	Day	8% 2 1 3 2 2 2 2 3 5% 70%	7627
	21st to end	Day	8% 4 1 4 3 3 3 3 5% 6% 60%	8404
June	1st to 10th	Day	5% 3 1 4 4 3 3 4 6% 9% 59%	2784
	11th to 20th	Day	2 2 1 3 3 3 3 3 4 7% 68%	2940
	21st to end	Day	4 3 1 4 3 4 5% 4 6% 7% 58%	2940
July	1st to 10th	Day	7% 5% 2 6% 4 4 5% 4 6% 7% 51%	6479
	11th to 20th	Day	3 2 1 4 3 4 5% 4 6% 9% 59%	6480
	21st to end	Day	4 2 1 4 4 4 5% 4 7% 10% 56%	6139
August	1st to 10th	Day	2 2 1 3 3 4 4 4 6% 9% 62%	5348
	11th to 20th	Day	2 2 1 4 3 4 5% 4 8% 10% 57%	5366
	21st to end	Day	4 3 1 5% 4 5% 5% 3 7% 9% 54%	5984
September	1st to 10th	Day	7% 5% 2 4 4 3 4 3 6% 8% 54%	2400
	11th to 20th	Day	7% 5% 2 4 3 3 4 4 5% 7% 54%	2259
	21st to end	Day	8% 2 1 3 2 2 2 2 4 5% 68%	2200
October	1st to 10th	Day	5% 3 1 2 1 1 1 2 3 3 77%	3590
	11th to 20th	Day	11% 3 1 3 2 2 3 2 3 4 66%	3346
	21st to end	Day	3 2 1 2 1 2 1 2 4 4 78%	3435
November	1st to 10th	Day	5% 2 1 3 2 2 2 2 4 6% 71%	1853
	11th to 20th	Day	1 4 1 3 2 2 3 2 4 6% 72%	1890
	21st to end	Day	7% 4 1 4 3 3 2 2 4 5% 64%	1890
December	1st to 10th	Day	3 3 2 5% 3 3 4 3 5% 6% 64%	3030
	11th to 20th	Day	2 4 1 5% 3 3 3 2 5% 6% 65%	3481
	21st to end	Day	3 4 1 3 2 2 2 2 3 5% 72%	4244
January	1st to 10th	Night	4 5% 2 5% 4 4 4 4 5% 6% 57%	8201
	11th to 20th	Night	2 2 1 2 2 2 2 2 4 5% 76%	7797
	21st to end	Night	5% 4 2 5% 4 3 4 4 5% 7% 57%	7765
February	1st to 10th	Night	4 4 1 4 2 3 3 3 4 6% 66%	2520
	11th to 20th	Night	5% 5% 2 4 3 3 3 3 5% 7% 60%	2458
	21st to end	Night	4 3 1 3 3 3 3 3 5% 6% 66%	2076
March	1st to 10th	Night	3 4 1 3 3 2 3 3 4 6% 68%	5494
	11th to 20th	Night	6% 4 2 4 2 3 2 2 4 6% 65%	5410
	21st to end	Night	2 3 1 4 3 3 3 3 5% 8% 67%	5094
April	1st to 10th	Night	5% 3 1 3 2 3 3 2 4 7% 67%	2100
	11th to 20th	Night	6% 4 1 4 3 3 3 3 4 5% 64%	2077
	21st to end	Night	5% 4 1 3 2 3 3 2 5% 7% 66%	2100
May	1st to 10th	Night	7% 3 1 3 3 3 3 3 5% 6% 63%	5662
	11th to 20th	Night	5% 3 1 3 2 2 3 2 4 6% 69%	5265
	21st to end	Night	8% 5% 1 3 3 3 3 3 5% 7% 59%	5803
June	1st to 10th	Night	4 3 1 5% 3 3 4 5% 8% 11% 52%	1828
	11th to 20th	Night	2 2 1 3 3 3 4 4 6% 8% 67%	1680
	21st to end	Night	3 2 1 4 3 5% 4 4 8% 10% 54%	1680
July	1st to 10th	Night	7% 5% 2 6% 4 4 5% 4 7% 9% 49%	3720
	11th to 20th	Night	3 3 2 5% 4 4 5% 5% 8% 12% 51%	3720
	21st to end	Night	3 3 2 5% 4 5% 6% 5% 9% 13% 46%	4944
August	1st to 10th	Night	2 3 1 4 4 4 5% 5% 9% 11% 51%	4464
	11th to 20th	Night	4 3 2 5% 4 4 5% 4 7% 11% 51%	4483
	21st to end	Night	6% 4 2 6% 4 5% 5% 4 7% 10% 46%	4993
September	1st to 10th	Night	6% 4 1 5% 3 3 4 3 7% 7% 57%	2000
	11th to 20th	Night	8% 4 2 5% 3 4 4 3 6% 7% 55%	2140
	21st to end	Night	6% 3 1 3 2 3 3 2 4 5% 68%	2200
October	1st to 10th	Night	4 2 1 2 2 2 2 2 3 4 76%	3590
	11th to 20th	Night	13% 2 1 2 2 3 3 2 4 5% 63%	3794
	21st to end	Night	6% 2 1 2 1 1 2 2 3 5% 75%	4332
November	1st to 10th	Night	5% 2 1 2 2 2 2 3 4 5% 73%	2665
	11th to 20th	Night	2 2 1 3 2 2 3 2 3 6% 74%	2730
	21st to end	Night	5% 4 1 4 2 3 3 2 4 5% 66%	2730
December	1st to 10th	Night	5% 4 2 5% 3 3 3 3 5% 6% 63%	4380
	11th to 20th	Night	3 2 1 3 2 3 3 3 4 7% 69%	4946
	21st to end	Night	3 3 1 4 3 3 3 2 4 6% 68%	6965

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	29% 3 5% 21% 32% 11%	4723
	11th to 20th	Day	13% 3 8% 19% 34% 24%	5238
	21st to end	Day	29% 3 5% 16% 32% 15%	6443
February	1st to 10th	Day	20% 3 7% 19% 31% 19%	2100
	11th to 20th	Day	27% 2 5% 19% 28% 18%	2059
	21st to end	Day	20% 3 4 13% 36% 25%	1730
March	1st to 10th	Day	20% 2 4 8% 31% 35%	4600
	11th to 20th	Day	23% 3 5% 16% 28% 25%	4784
	21st to end	Day	22% 5% 6% 19% 31% 18%	6101
April	1st to 10th	Day	18% 3 6% 15% 33% 26%	2520
	11th to 20th	Day	21% 3 6% 17% 26% 27%	2494
	21st to end	Day	15% 4 7% 21% 32% 21%	2520
May	1st to 10th	Day	24% 3 8% 20% 22% 23%	7271
	11th to 20th	Day	18% 3 5% 13% 25% 36%	7631
	21st to end	Day	25% 5% 10% 17% 14% 30%	8405
June	1st to 10th	Day	21% 6% 12% 26% 19% 15%	2784
	11th to 20th	Day	16% 5% 8% 18% 25% 28%	2940
	21st to end	Day	22% 7% 11% 23% 24% 14%	2940
July	1st to 10th	Day	31% 7% 10% 23% 22% 6%	6411
	11th to 20th	Day	19% 6% 14% 35% 21% 4	6405
	21st to end	Day	21% 7% 18% 31% 21% 2	5966
August	1st to 10th	Day	15% 7% 13% 30% 23% 12%	3892
	11th to 20th	Day	17% 6% 11% 21% 31% 13%	3882
	21st to end	Day	25% 6% 14% 25% 24% 5%	4311
September	1st to 10th	Day	27% 8% 11% 20% 23% 12%	2400
	11th to 20th	Day	28% 5% 9% 19% 27% 11%	2259
	21st to end	Day	20% 3 6% 20% 33% 18%	2200
October	1st to 10th	Day	14% 3 5% 11% 33% 33%	3590
	11th to 20th	Day	24% 3 8% 14% 25% 25%	3346
	21st to end	Day	12% 2 3 20% 37% 26%	3435
November	1st to 10th	Day	17% 2 6% 16% 38% 22%	1853
	11th to 20th	Day	15% 2 6% 23% 34% 20%	1890
	21st to end	Day	24% 2 4 18% 30% 23%	1890
December	1st to 10th	Day	22% 2 6% 26% 27% 17%	3030
	11th to 20th	Day	21% 2 5% 18% 37% 18%	3479
	21st to end	Day	17% 3 5% 23% 34% 18%	4244
January	1st to 10th	Night	28% 3 5% 23% 33% 8%	8202
	11th to 20th	Night	11% 3 8% 22% 38% 19%	7797
	21st to end	Night	26% 4 6% 16% 32% 16%	7765
February	1st to 10th	Night	21% 3 5% 18% 29% 24%	2520
	11th to 20th	Night	25% 3 7% 19% 27% 20%	2458
	21st to end	Night	19% 2 4 14% 32% 29%	2076
March	1st to 10th	Night	18% 2 4 11% 28% 38%	5494
	11th to 20th	Night	21% 4 6% 15% 22% 33%	5410
	21st to end	Night	16% 4 8% 18% 29% 24%	5094
April	1st to 10th	Night	19% 3 7% 17% 30% 25%	2100
	11th to 20th	Night	23% 4 6% 18% 23% 26%	2077
	21st to end	Night	18% 4 9% 21% 25% 23%	2100
May	1st to 10th	Night	22% 4 10% 20% 22% 22%	5660
	11th to 20th	Night	17% 4 5% 14% 23% 37%	5266
	21st to end	Night	25% 5% 14% 13% 9% 33%	5805
June	1st to 10th	Night	23% 8% 15% 21% 19% 13%	1828
	11th to 20th	Night	14% 6% 12% 17% 25% 26%	1680
	21st to end	Night	22% 7% 14% 25% 19% 14%	1680
July	1st to 10th	Night	31% 7% 15% 27% 17% 3	3680
	11th to 20th	Night	24% 6% 15% 29% 20% 5%	3672
	21st to end	Night	26% 8% 17% 30% 17% 2	4805
August	1st to 10th	Night	25% 7% 15% 24% 18% 12%	3244
	11th to 20th	Night	19% 6% 10% 25% 32% 9%	3243
	21st to end	Night	29% 8% 15% 22% 21% 6%	3597
September	1st to 10th	Night	25% 7% 14% 20% 21% 12%	2000
	11th to 20th	Night	27% 7% 11% 21% 22% 12%	2140
	21st to end	Night	20% 4 7% 21% 31% 18%	2200
October	1st to 10th	Night	14% 3 6% 11% 31% 36%	3590
	11th to 20th	Night	25% 2 6% 15% 27% 25%	3794
	21st to end	Night	15% 2 3 17% 36% 27%	4332
November	1st to 10th	Night	15% 3 5% 18% 33% 26%	2665
	11th to 20th	Night	14% 3 5% 20% 39% 20%	2730
	21st to end	Night	21% 3 5% 18% 34% 19%	2730
December	1st to 10th	Night	23% 3 6% 24% 33% 12%	4380
	11th to 20th	Night	17% 2 4 15% 39% 23%	4947
	21st to end	Night	19% 3 5% 20% 36% 17%	6965

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% 15% 42% 25% 6% 2	330
	11th to 20th	Day	8% 18% 39% 25% 9% 2	330
	21st to end	Day	6% 14% 37% 32% 10% 1	363
February	1st to 10th	Day	6% 14% 46% 26% 8%	330
	11th to 20th	Day	12% 17% 43% 20% 7% 1	330
	21st to end	Day	10% 16% 49% 18% 7%	273
March	1st to 10th	Day	6% 15% 46% 25% 7% 1	330
	11th to 20th	Day	15% 14% 35% 23% 12% 1	362
	21st to end	Day	8% 21% 40% 22% 9% 1	594
April	1st to 10th	Day	8% 18% 45% 22% 7% 1	540
	11th to 20th	Day	10% 20% 44% 20% 5% 1	532
	21st to end	Day	6% 20% 40% 26% 8% 1	540
May	1st to 10th	Day	5% 16% 41% 29% 8% 1	616
	11th to 20th	Day	9% 12% 29% 33% 17% 2	775
	21st to end	Day	8% 7% 33% 37% 14% 1	844
June	1st to 10th	Day	6% 4 25% 41% 20% 4	780
	11th to 20th	Day	3 4 28% 42% 20% 3	780
	21st to end	Day	4 3 24% 41% 25% 3	780
July	1st to 10th	Day	7% 1 13% 35% 34% 11%	771
	11th to 20th	Day	4 1 6% 39% 41% 10%	768
	21st to end	Day	3 1 8% 34% 41% 13%	660
August	1st to 10th	Day	2 2 9% 40% 40% 7%	527
	11th to 20th	Day	4 1 9% 38% 37% 10%	517
	21st to end	Day	7% 1 9% 41% 32% 10%	583
September	1st to 10th	Day	7% 1 13% 46% 27% 6%	530
	11th to 20th	Day	6% 1 15% 40% 31% 7%	389
	21st to end	Day	9% 4 22% 35% 25% 5%	330
October	1st to 10th	Day	12% 4 24% 35% 22% 3	330
	11th to 20th	Day	9% 6% 27% 39% 14% 4	330
	21st to end	Day	10% 9% 25% 34% 17% 5%	363
November	1st to 10th	Day	9% 10% 38% 27% 14% 2	330
	11th to 20th	Day	5% 13% 34% 32% 11% 5%	330
	21st to end	Day	13% 16% 40% 20% 9% 2	330
December	1st to 10th	Day	9% 12% 43% 26% 9% 1	330
	11th to 20th	Day	5% 11% 43% 33% 8%	330
	21st to end	Day	10% 16% 41% 26% 7%	363
January	1st to 10th	Night	6% 13% 40% 32% 8% 1	1050
	11th to 20th	Night	5% 10% 42% 33% 8% 1	896
	21st to end	Night	6% 11% 41% 35% 7%	924
February	1st to 10th	Night	6% 15% 44% 30% 6%	840
	11th to 20th	Night	8% 15% 46% 27% 4	824
	21st to end	Night	8% 14% 48% 27% 3	692
March	1st to 10th	Night	8% 13% 45% 30% 5%	840
	11th to 20th	Night	10% 16% 37% 29% 7%	814
	21st to end	Night	5% 13% 53% 24% 4	693
April	1st to 10th	Night	7% 15% 48% 26% 4	630
	11th to 20th	Night	7% 15% 54% 22% 3	623
	21st to end	Night	6% 15% 48% 25% 5%	630
May	1st to 10th	Night	6% 12% 45% 33% 4	630
	11th to 20th	Night	8% 9% 38% 33% 11%	621
	21st to end	Night	8% 6% 42% 36% 7%	683
June	1st to 10th	Night	5% 5% 35% 45% 9%	630
	11th to 20th	Night	2 5% 42% 45% 7%	630
	21st to end	Night	4 2 31% 48% 14%	630
July	1st to 10th	Night	6% 1 19% 46% 27% 1	615
	11th to 20th	Night	3 1 14% 49% 32% 1	612
	21st to end	Night	3 1 11% 49% 35% 2	687
August	1st to 10th	Night	3 13% 45% 36% 2	597
	11th to 20th	Night	5% 1 11% 50% 31% 1	594
	21st to end	Night	6% 1 13% 47% 32% 1	660
September	1st to 10th	Night	6% 1 16% 51% 25% 1	600
	11th to 20th	Night	9% 2 19% 53% 17%	600
	21st to end	Night	7% 4 20% 49% 20% 1	600
October	1st to 10th	Night	8% 4 28% 43% 17%	600
	11th to 20th	Night	8% 6% 32% 40% 13% 1	735
	21st to end	Night	8% 9% 28% 36% 18% 1	924
November	1st to 10th	Night	6% 7% 32% 39% 15% 1	1025
	11th to 20th	Night	3 10% 35% 38% 13% 1	1050
	21st to end	Night	8% 11% 34% 34% 13% 1	1050
December	1st to 10th	Night	7% 12% 38% 35% 7% 1	1050
	11th to 20th	Night	6% 11% 42% 33% 7%	1050
	21st to end	Night	8% 14% 43% 28% 7%	1155

Page generated at 2026-07-28 01:25:26. Version ac07

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