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 2025-03-27.

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% 4 1 4 3 3 3 3 5% 7% 63%	113359
	Night	5% 3 1 4 3 3 3 3 5% 7% 63%	114794
Transparency	Day	21% 4 8% 20% 28% 19%	113121
	Night	21% 4 8% 19% 28% 19%	114623
Seeing	Day	7% 9% 28% 33% 20% 4	15609
	Night	6% 9% 35% 37% 13% 1	25781

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	7% 9% 3 5% 3 3 2 3 4 5% 57%	3638
	11th to 20th	Day	2 3 1 3 2 3 3 3 4 6% 72%	4026
	21st to end	Day	5% 5% 2 6% 4 3 3 3 5% 6% 57%	4969
February	1st to 10th	Day	3 5% 1 4 3 3 3 3 5% 6% 65%	2000
	11th to 20th	Day	5% 6% 2 6% 3 3 2 2 4 6% 60%	1949
	21st to end	Day	3 5% 2 4 2 3 3 3 4 6% 65%	1650
March	1st to 10th	Day	3 4 1 4 3 3 3 3 5% 6% 66%	3230
	11th to 20th	Day	11% 4 1 4 3 3 3 3 5% 8% 55%	3373
	21st to end	Day	3 4 1 7% 4 4 4 4 5% 7% 56%	4238
April	1st to 10th	Day	3 3 1 3 3 3 3 2 4 6% 70%	2280
	11th to 20th	Day	6% 4 1 4 3 2 3 2 5% 5% 65%	2251
	21st to end	Day	3 3 1 3 2 2 2 3 5% 7% 69%	2280
May	1st to 10th	Day	5% 2 1 3 2 2 3 3 4 5% 70%	3918
	11th to 20th	Day	11% 3 1 4 3 3 3 3 4 6% 61%	4082
	21st to end	Day	5% 3 1 2 2 3 2 3 4 5% 70%	4489
June	1st to 10th	Day	5% 3 1 4 4 3 3 4 6% 9% 59%	2518
	11th to 20th	Day	2 2 1 3 3 3 3 3 4 7% 68%	2660
	21st to end	Day	4 3 1 3 3 4 5% 4 6% 7% 60%	2660
July	1st to 10th	Day	8% 4 2 6% 3 4 4 4 6% 7% 52%	4430
	11th to 20th	Day	3 2 1 4 4 4 5% 4 6% 9% 58%	4430
	21st to end	Day	5% 3 2 3 3 4 4 4 7% 10% 55%	4184
August	1st to 10th	Day	2 2 1 3 3 4 4 4 6% 9% 63%	3784
	11th to 20th	Day	3 2 1 3 3 3 3 3 6% 9% 65%	3726
	21st to end	Day	5% 3 2 5% 3 4 5% 3 7% 9% 54%	4180
September	1st to 10th	Day	7% 5% 2 4 4 3 4 3 7% 8% 54%	2280
	11th to 20th	Day	8% 5% 2 4 3 3 4 4 5% 7% 54%	2146
	21st to end	Day	8% 2 1 3 2 2 2 2 4 5% 69%	2090
October	1st to 10th	Day	5% 3 1 2 1 1 1 2 3 3 78%	3480
	11th to 20th	Day	11% 3 1 3 2 2 3 2 3 4 66%	3243
	21st to end	Day	3 2 1 2 1 2 1 2 4 4 78%	3328
November	1st to 10th	Day	5% 3 1 3 2 2 2 2 4 6% 70%	1763
	11th to 20th	Day	1 4 1 3 2 2 3 2 4 6% 72%	1800
	21st to end	Day	7% 4 1 4 4 3 2 2 4 5% 63%	1800
December	1st to 10th	Day	4 3 1 5% 3 3 4 3 5% 6% 63%	2940
	11th to 20th	Day	2 4 1 5% 3 4 3 2 5% 6% 65%	3391
	21st to end	Day	3 4 1 3 2 2 2 2 3 5% 72%	4153
January	1st to 10th	Night	4 6% 3 5% 4 4 3 3 5% 5% 58%	6327
	11th to 20th	Night	2 2 1 3 2 3 3 2 4 6% 72%	5999
	21st to end	Night	3 5% 2 5% 3 3 4 4 5% 7% 59%	6003
February	1st to 10th	Night	4 4 1 5% 2 3 3 3 4 6% 65%	2400
	11th to 20th	Night	6% 5% 2 4 4 3 3 3 4 7% 60%	2338
	21st to end	Night	5% 4 1 3 3 3 3 3 5% 6% 64%	1980
March	1st to 10th	Night	3 4 2 4 3 2 3 3 4 6% 68%	3854
	11th to 20th	Night	9% 5% 2 5% 3 3 3 3 4 6% 57%	3810
	21st to end	Night	3 4 2 5% 3 3 3 3 5% 7% 63%	3542
April	1st to 10th	Night	4 3 1 3 2 3 3 2 4 7% 68%	1900
	11th to 20th	Night	6% 4 1 4 3 3 3 3 4 6% 64%	1877
	21st to end	Night	4 3 1 3 2 3 3 2 5% 7% 68%	1900
May	1st to 10th	Night	5% 3 1 2 3 2 3 2 4 5% 70%	3052
	11th to 20th	Night	9% 4 2 4 3 3 3 2 4 6% 60%	2823
	21st to end	Night	6% 3 1 2 3 2 2 3 4 6% 68%	3098
June	1st to 10th	Night	4 3 1 5% 3 3 5% 5% 8% 11% 53%	1654
	11th to 20th	Night	2 2 1 3 3 3 4 3 6% 7% 67%	1520
	21st to end	Night	3 2 1 4 3 4 4 4 8% 10% 55%	1520
July	1st to 10th	Night	4 3 2 5% 4 4 5% 5% 7% 9% 53%	2540
	11th to 20th	Night	3 3 2 5% 4 4 5% 5% 8% 10% 50%	2540
	21st to end	Night	4 3 1 4 4 4 5% 5% 8% 12% 50%	3368
August	1st to 10th	Night	2 3 1 5% 5% 5% 5% 6% 9% 11% 48%	3155
	11th to 20th	Night	3 2 1 3 3 3 4 3 6% 10% 61%	3113
	21st to end	Night	4 3 2 6% 4 5% 5% 4 7% 10% 48%	3487
September	1st to 10th	Night	6% 4 1 5% 3 3 4 3 7% 7% 57%	1900
	11th to 20th	Night	8% 4 2 4 3 3 4 3 6% 6% 56%	2033
	21st to end	Night	6% 3 1 3 2 3 3 2 3 5% 69%	2090
October	1st to 10th	Night	4 2 1 2 2 1 2 2 3 4 76%	3480
	11th to 20th	Night	13% 2 1 2 2 3 3 2 4 5% 64%	3677
	21st to end	Night	6% 2 1 2 1 1 2 2 3 5% 75%	4198
November	1st to 10th	Night	5% 2 1 2 2 2 2 3 4 5% 72%	2535
	11th to 20th	Night	2 3 1 3 2 2 3 2 3 6% 74%	2600
	21st to end	Night	6% 4 1 4 2 3 3 2 4 5% 65%	2600
December	1st to 10th	Night	4 5% 2 5% 3 3 3 3 5% 6% 62%	4250
	11th to 20th	Night	3 3 1 3 3 3 3 3 4 7% 68%	4816
	21st to end	Night	3 4 1 4 3 3 3 2 4 6% 68%	6815

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	30% 3 5% 22% 30% 10%	3639
	11th to 20th	Day	14% 3 7% 23% 34% 19%	4026
	21st to end	Day	27% 4 6% 18% 30% 16%	4969
February	1st to 10th	Day	21% 4 8% 19% 29% 19%	2000
	11th to 20th	Day	27% 3 5% 19% 27% 19%	1959
	21st to end	Day	20% 3 4 12% 35% 25%	1650
March	1st to 10th	Day	18% 3 5% 12% 33% 29%	3230
	11th to 20th	Day	27% 5% 7% 21% 28% 12%	3373
	21st to end	Day	23% 6% 7% 19% 28% 18%	4238
April	1st to 10th	Day	17% 3 6% 15% 32% 28%	2280
	11th to 20th	Day	22% 3 6% 16% 26% 27%	2254
	21st to end	Day	15% 4 8% 22% 32% 20%	2280
May	1st to 10th	Day	16% 3 7% 18% 20% 35%	3918
	11th to 20th	Day	25% 5% 7% 18% 23% 22%	4086
	21st to end	Day	17% 4 7% 16% 19% 38%	4489
June	1st to 10th	Day	21% 7% 12% 26% 19% 15%	2518
	11th to 20th	Day	16% 5% 8% 17% 24% 29%	2660
	21st to end	Day	20% 7% 11% 23% 24% 15%	2660
July	1st to 10th	Day	30% 6% 12% 22% 22% 8%	4361
	11th to 20th	Day	21% 6% 13% 30% 24% 5%	4355
	21st to end	Day	21% 8% 12% 29% 26% 3	4051
August	1st to 10th	Day	15% 7% 14% 30% 22% 12%	3772
	11th to 20th	Day	16% 6% 11% 21% 32% 14%	3762
	21st to end	Day	25% 6% 14% 26% 24% 5%	4179
September	1st to 10th	Day	27% 8% 11% 19% 23% 13%	2280
	11th to 20th	Day	28% 5% 10% 18% 27% 11%	2146
	21st to end	Day	20% 3 6% 20% 34% 18%	2090
October	1st to 10th	Day	13% 3 5% 11% 33% 34%	3480
	11th to 20th	Day	24% 3 8% 14% 26% 25%	3243
	21st to end	Day	12% 2 3 20% 36% 27%	3328
November	1st to 10th	Day	17% 2 7% 16% 37% 21%	1763
	11th to 20th	Day	15% 3 6% 23% 34% 19%	1800
	21st to end	Day	24% 2 4 16% 30% 24%	1800
December	1st to 10th	Day	22% 2 6% 26% 27% 17%	2940
	11th to 20th	Day	21% 2 5% 18% 37% 17%	3389
	21st to end	Day	17% 3 5% 23% 35% 18%	4153
January	1st to 10th	Night	28% 3 6% 24% 31% 8%	6327
	11th to 20th	Night	14% 4 9% 21% 36% 17%	5999
	21st to end	Night	23% 5% 8% 19% 29% 17%	6003
February	1st to 10th	Night	22% 3 5% 19% 27% 24%	2400
	11th to 20th	Night	25% 4 7% 19% 26% 20%	2338
	21st to end	Night	20% 2 5% 14% 30% 30%	1980
March	1st to 10th	Night	17% 3 5% 13% 27% 34%	3854
	11th to 20th	Night	27% 5% 7% 20% 24% 17%	3810
	21st to end	Night	20% 5% 7% 21% 26% 22%	3542
April	1st to 10th	Night	17% 3 7% 17% 29% 27%	1900
	11th to 20th	Night	22% 4 7% 18% 23% 27%	1877
	21st to end	Night	17% 4 10% 21% 26% 22%	1900
May	1st to 10th	Night	16% 5% 8% 15% 17% 39%	3052
	11th to 20th	Night	24% 7% 9% 19% 18% 23%	2824
	21st to end	Night	17% 5% 11% 11% 12% 44%	3099
June	1st to 10th	Night	22% 9% 15% 21% 19% 14%	1654
	11th to 20th	Night	15% 6% 12% 16% 25% 27%	1520
	21st to end	Night	21% 7% 14% 25% 19% 14%	1520
July	1st to 10th	Night	25% 8% 17% 28% 19% 4	2500
	11th to 20th	Night	26% 7% 12% 22% 26% 7%	2492
	21st to end	Night	24% 7% 14% 30% 23% 3	3263
August	1st to 10th	Night	25% 7% 15% 23% 17% 13%	3144
	11th to 20th	Night	18% 6% 10% 24% 33% 9%	3143
	21st to end	Night	29% 8% 14% 22% 20% 6%	3487
September	1st to 10th	Night	24% 8% 14% 19% 22% 13%	1900
	11th to 20th	Night	27% 7% 11% 20% 22% 13%	2033
	21st to end	Night	20% 4 6% 21% 32% 18%	2090
October	1st to 10th	Night	13% 3 5% 11% 31% 37%	3480
	11th to 20th	Night	25% 2 6% 14% 28% 25%	3677
	21st to end	Night	15% 2 3 17% 36% 27%	4198
November	1st to 10th	Night	15% 3 6% 18% 32% 26%	2535
	11th to 20th	Night	13% 3 5% 21% 38% 20%	2600
	21st to end	Night	22% 4 5% 16% 34% 20%	2600
December	1st to 10th	Night	23% 3 6% 24% 33% 11%	4250
	11th to 20th	Night	17% 2 4 15% 39% 23%	4817
	21st to end	Night	19% 3 6% 19% 36% 17%	6815

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	10% 14% 42% 26% 6% 2	300
	11th to 20th	Day	9% 18% 40% 23% 9% 2	300
	21st to end	Day	5% 14% 37% 33% 11% 1	330
February	1st to 10th	Day	6% 14% 46% 26% 8%	300
	11th to 20th	Day	10% 17% 45% 20% 7% 1	300
	21st to end	Day	10% 17% 47% 18% 6%	249
March	1st to 10th	Day	6% 14% 46% 26% 7% 1	300
	11th to 20th	Day	15% 14% 36% 22% 12% 1	330
	21st to end	Day	8% 22% 41% 19% 9%	531
April	1st to 10th	Day	6% 19% 45% 22% 7% 1	460
	11th to 20th	Day	11% 17% 44% 23% 5% 1	452
	21st to end	Day	6% 17% 41% 27% 8% 1	460
May	1st to 10th	Day	3 16% 40% 30% 10% 1	529
	11th to 20th	Day	8% 9% 28% 35% 17% 2	675
	21st to end	Day	7% 8% 33% 36% 14% 1	734
June	1st to 10th	Day	5% 4 23% 42% 22% 4	680
	11th to 20th	Day	3 4 28% 42% 21% 3	680
	21st to end	Day	4 1 20% 42% 28% 4	680
July	1st to 10th	Day	6% 1 12% 32% 37% 12%	671
	11th to 20th	Day	4 5% 38% 42% 10%	668
	21st to end	Day	3 1 8% 33% 40% 15%	571
August	1st to 10th	Day	2 2 8% 39% 41% 8%	487
	11th to 20th	Day	4 1 8% 39% 37% 10%	477
	21st to end	Day	7% 1 9% 40% 32% 11%	539
September	1st to 10th	Day	6% 1 11% 45% 29% 7%	490
	11th to 20th	Day	6% 1 13% 40% 33% 8%	356
	21st to end	Day	10% 4 18% 35% 27% 6%	300
October	1st to 10th	Day	13% 3 24% 35% 22% 4	300
	11th to 20th	Day	9% 6% 25% 41% 15% 4	300
	21st to end	Day	10% 9% 25% 33% 17% 5%	330
November	1st to 10th	Day	10% 10% 38% 25% 14% 3	300
	11th to 20th	Day	5% 13% 35% 32% 10% 5%	300
	21st to end	Day	13% 16% 40% 20% 9% 3	300
December	1st to 10th	Day	9% 11% 43% 26% 10% 1	300
	11th to 20th	Day	6% 11% 44% 33% 7%	300
	21st to end	Day	10% 17% 43% 23% 6%	330
January	1st to 10th	Night	6% 13% 40% 33% 9% 1	1000
	11th to 20th	Night	6% 10% 42% 33% 8% 1	854
	21st to end	Night	5% 11% 41% 35% 8%	880
February	1st to 10th	Night	6% 15% 44% 29% 6%	800
	11th to 20th	Night	8% 15% 46% 27% 4	784
	21st to end	Night	8% 13% 49% 27% 3	660
March	1st to 10th	Night	8% 13% 44% 30% 5%	800
	11th to 20th	Night	10% 16% 38% 29% 7%	775
	21st to end	Night	5% 14% 53% 24% 4	647
April	1st to 10th	Night	5% 15% 49% 26% 4	570
	11th to 20th	Night	7% 14% 53% 23% 3	563
	21st to end	Night	5% 15% 49% 26% 5%	570
May	1st to 10th	Night	5% 11% 46% 33% 4	570
	11th to 20th	Night	8% 8% 37% 35% 11%	561
	21st to end	Night	8% 6% 41% 37% 8%	617
June	1st to 10th	Night	4 5% 34% 47% 10%	570
	11th to 20th	Night	2 4 42% 45% 7%	570
	21st to end	Night	4 1 28% 51% 16% 1	570
July	1st to 10th	Night	5% 1 17% 47% 30% 1	555
	11th to 20th	Night	4 1 13% 49% 33% 1	552
	21st to end	Night	3 1 10% 47% 38% 2	624
August	1st to 10th	Night	4 11% 46% 38% 2	567
	11th to 20th	Night	5% 1 11% 50% 32% 1	564
	21st to end	Night	6% 1 13% 47% 33% 1	627
September	1st to 10th	Night	6% 1 15% 51% 26% 1	570
	11th to 20th	Night	9% 2 18% 53% 17%	570
	21st to end	Night	6% 4 20% 48% 21% 1	570
October	1st to 10th	Night	8% 4 27% 43% 17%	570
	11th to 20th	Night	8% 6% 31% 40% 13% 1	698
	21st to end	Night	8% 9% 28% 35% 18% 1	878
November	1st to 10th	Night	6% 7% 31% 39% 15% 1	975
	11th to 20th	Night	3 10% 36% 37% 14% 1	1000
	21st to end	Night	8% 11% 34% 33% 13% 1	1000
December	1st to 10th	Night	7% 12% 37% 36% 8% 1	1000
	11th to 20th	Night	6% 11% 42% 33% 8%	1000
	21st to end	Night	8% 14% 43% 28% 7%	1100

Page generated at 2025-03-24 07:04:32. Version ac07

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