Jefferson City
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Jefferson City clear sky chart from 2005-11-06 to 2024-11-03.

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	12% 7% 3 6% 4 4 4 4 5% 7% 43%	101216
	Night	13% 8% 3 6% 4 4 4 3 5% 7% 45%	97861
Transparency	Day	39% 6% 12% 25% 15% 2	101016
	Night	40% 5% 11% 25% 16% 3	97732
Seeing	Day	17% 12% 28% 26% 14% 3	15635
	Night	18% 12% 30% 28% 12% 1	25435

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	13% 13% 4 9% 5% 4 4 3 5% 5% 35%	2632
	11th to 20th	Day	13% 11% 4 8% 5% 6% 5% 4 3 5% 36%	2850
	21st to end	Day	19% 14% 6% 7% 4 3 4 3 3 5% 32%	3135
February	1st to 10th	Day	15% 12% 4 9% 5% 4 3 3 5% 5% 33%	1710
	11th to 20th	Day	15% 12% 3 5% 4 3 4 3 5% 6% 41%	1726
	21st to end	Day	16% 10% 4 6% 4 4 4 4 5% 5% 38%	1570
March	1st to 10th	Day	18% 9% 3 6% 3 3 3 2 4 5% 44%	3392
	11th to 20th	Day	13% 7% 2 5% 4 3 3 2 4 6% 50%	3480
	21st to end	Day	17% 11% 3 9% 5% 4 5% 4 5% 6% 32%	3874
April	1st to 10th	Day	13% 7% 3 6% 5% 4 3 4 4 6% 45%	2280
	11th to 20th	Day	17% 8% 2 5% 4 4 4 4 4 6% 42%	2254
	21st to end	Day	20% 9% 3 7% 4 4 4 3 5% 6% 35%	2280
May	1st to 10th	Day	15% 8% 3 8% 5% 4 4 4 7% 9% 34%	3952
	11th to 20th	Day	17% 8% 3 7% 4 4 4 3 5% 7% 38%	4257
	21st to end	Day	11% 6% 2 6% 5% 5% 5% 4 6% 7% 43%	4824
June	1st to 10th	Day	7% 4 2 5% 4 4 5% 4 8% 10% 45%	2660
	11th to 20th	Day	8% 4 2 5% 4 4 4 4 6% 10% 48%	2660
	21st to end	Day	6% 3 1 5% 4 4 5% 4 7% 10% 50%	2660
July	1st to 10th	Day	13% 7% 2 6% 5% 3 4 4 6% 9% 41%	4440
	11th to 20th	Day	4 5% 2 6% 5% 4 5% 3 7% 10% 49%	4257
	21st to end	Day	6% 5% 2 6% 5% 5% 5% 6% 8% 12% 40%	4465
August	1st to 10th	Day	5% 4 2 5% 4 4 4 4 8% 11% 51%	4104
	11th to 20th	Day	12% 5% 2 6% 4 4 4 3 6% 8% 45%	3883
	21st to end	Day	6% 5% 2 5% 4 4 4 4 6% 8% 53%	4180
September	1st to 10th	Day	11% 4 2 5% 4 4 4 4 5% 7% 50%	2280
	11th to 20th	Day	10% 6% 2 5% 4 4 4 3 5% 6% 52%	2280
	21st to end	Day	7% 6% 2 5% 4 3 4 4 5% 7% 53%	1997
October	1st to 10th	Day	10% 5% 2 5% 3 3 4 3 5% 5% 55%	1900
	11th to 20th	Day	15% 6% 2 5% 3 3 2 2 3 5% 53%	1900
	21st to end	Day	18% 7% 2 6% 3 3 2 2 4 5% 47%	2090
November	1st to 10th	Day	11% 6% 2 4 3 3 3 2 6% 6% 54%	1793
	11th to 20th	Day	14% 8% 2 5% 3 4 3 3 5% 6% 47%	1710
	21st to end	Day	17% 9% 2 5% 3 3 3 3 4 6% 44%	1520
December	1st to 10th	Day	13% 10% 3 6% 4 3 3 3 5% 6% 42%	1520
	11th to 20th	Day	13% 10% 4 7% 5% 4 3 3 5% 5% 42%	1918
	21st to end	Day	20% 14% 4 10% 5% 4 4 3 5% 5% 25%	2783
January	1st to 10th	Night	12% 11% 7% 10% 5% 4 4 3 3 4 36%	4318
	11th to 20th	Night	13% 10% 4 11% 6% 7% 5% 4 4 4 31%	4120
	21st to end	Night	21% 16% 5% 7% 3 3 3 2 4 5% 31%	4532
February	1st to 10th	Night	14% 12% 4 8% 5% 3 4 4 5% 5% 35%	2470
	11th to 20th	Night	14% 8% 3 8% 4 4 4 3 5% 6% 42%	2338
	21st to end	Night	16% 10% 4 7% 4 4 3 2 4 5% 41%	1884
March	1st to 10th	Night	19% 10% 2 5% 3 2 2 3 4 4 46%	3490
	11th to 20th	Night	14% 6% 2 5% 3 3 3 3 4 6% 51%	3480
	21st to end	Night	17% 11% 4 8% 5% 5% 4 4 5% 6% 31%	3756
April	1st to 10th	Night	11% 7% 2 6% 3 3 3 3 4 7% 49%	1900
	11th to 20th	Night	13% 9% 3 6% 3 3 4 3 4 8% 46%	1875
	21st to end	Night	17% 8% 2 6% 4 3 4 3 5% 7% 41%	1900
May	1st to 10th	Night	15% 9% 3 5% 4 3 3 4 6% 8% 39%	2945
	11th to 20th	Night	12% 7% 3 8% 4 4 4 3 5% 8% 41%	2644
	21st to end	Night	10% 5% 2 6% 5% 4 4 4 6% 9% 45%	2743
June	1st to 10th	Night	8% 3 2 5% 3 4 4 4 7% 9% 51%	1520
	11th to 20th	Night	6% 5% 1 4 4 4 4 3 6% 11% 52%	1520
	21st to end	Night	3 3 1 3 3 3 4 3 7% 11% 58%	1520
July	1st to 10th	Night	11% 6% 2 6% 3 4 4 4 5% 9% 46%	2530
	11th to 20th	Night	4 3 2 4 3 4 4 3 6% 10% 57%	2709
	21st to end	Night	5% 5% 2 6% 4 5% 4 4 6% 10% 48%	3098
August	1st to 10th	Night	4 3 1 4 3 2 3 3 5% 9% 63%	2836
	11th to 20th	Night	11% 6% 2 5% 4 3 4 3 5% 7% 51%	2949
	21st to end	Night	5% 3 1 4 3 3 4 3 6% 9% 58%	3476
September	1st to 10th	Night	11% 4 2 4 3 3 4 3 4 7% 57%	1900
	11th to 20th	Night	9% 5% 2 5% 3 4 4 4 6% 7% 52%	1900
	21st to end	Night	8% 5% 1 5% 4 4 4 3 4 7% 55%	2159
October	1st to 10th	Night	8% 4 2 4 3 3 3 3 5% 6% 60%	2280
	11th to 20th	Night	13% 6% 2 4 3 3 3 3 4 5% 53%	2280
	21st to end	Night	17% 8% 2 5% 3 3 3 3 3 4 50%	2508
November	1st to 10th	Night	10% 6% 1 4 3 3 3 2 4 5% 58%	2329
	11th to 20th	Night	13% 7% 3 6% 4 3 2 2 4 6% 50%	2470
	21st to end	Night	16% 9% 3 7% 3 3 3 3 4 5% 46%	2659
December	1st to 10th	Night	14% 11% 3 6% 5% 4 4 3 5% 6% 39%	2660
	11th to 20th	Night	16% 10% 4 6% 4 3 4 3 4 5% 41%	3279
	21st to end	Night	19% 20% 5% 9% 4 4 3 3 3 5% 25%	4884

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	50% 5% 10% 23% 11% 1	2633
	11th to 20th	Day	50% 4 12% 22% 12%	2850
	21st to end	Day	56% 4 10% 16% 13% 2	3135
February	1st to 10th	Day	54% 4 9% 20% 12% 1	1710
	11th to 20th	Day	45% 5% 11% 20% 15% 3	1735
	21st to end	Day	46% 5% 8% 22% 14% 4	1570
March	1st to 10th	Day	44% 4 7% 22% 18% 4	3392
	11th to 20th	Day	35% 5% 11% 27% 17% 5%	3480
	21st to end	Day	51% 7% 15% 20% 7% 1	3874
April	1st to 10th	Day	39% 6% 12% 25% 17% 2	2280
	11th to 20th	Day	42% 6% 10% 25% 15% 3	2254
	21st to end	Day	50% 4 11% 21% 13% 1	2280
May	1st to 10th	Day	44% 9% 13% 21% 12% 1	3987
	11th to 20th	Day	44% 8% 10% 24% 13% 1	4261
	21st to end	Day	38% 7% 10% 26% 18% 1	4837
June	1st to 10th	Day	31% 10% 15% 27% 16% 2	2660
	11th to 20th	Day	30% 8% 13% 29% 17% 4	2660
	21st to end	Day	28% 8% 17% 28% 16% 4	2660
July	1st to 10th	Day	39% 7% 12% 25% 15% 2	4371
	11th to 20th	Day	28% 8% 14% 32% 16% 2	4183
	21st to end	Day	32% 10% 20% 28% 9% 1	4325
August	1st to 10th	Day	25% 8% 17% 35% 15% 1	4090
	11th to 20th	Day	37% 7% 13% 27% 16% 1	3922
	21st to end	Day	27% 7% 15% 34% 14% 4	4179
September	1st to 10th	Day	33% 6% 11% 25% 21% 5%	2280
	11th to 20th	Day	32% 5% 9% 27% 24% 3	2280
	21st to end	Day	30% 6% 9% 27% 24% 4	1997
October	1st to 10th	Day	31% 5% 9% 23% 28% 4	1900
	11th to 20th	Day	35% 3 7% 26% 23% 6%	1900
	21st to end	Day	41% 4 8% 25% 19% 3	2090
November	1st to 10th	Day	31% 4 13% 24% 22% 5%	1793
	11th to 20th	Day	38% 4 8% 24% 22% 4	1710
	21st to end	Day	42% 4 9% 29% 15% 1	1520
December	1st to 10th	Day	43% 4 11% 29% 11% 1	1520
	11th to 20th	Day	44% 4 11% 25% 14% 2	1915
	21st to end	Day	61% 5% 10% 14% 9% 1	2783
January	1st to 10th	Night	52% 4 10% 23% 11% 1	4318
	11th to 20th	Night	57% 4 10% 19% 9% 1	4120
	21st to end	Night	58% 3 10% 20% 8% 1	4532
February	1st to 10th	Night	50% 6% 10% 20% 13% 2	2470
	11th to 20th	Night	44% 5% 11% 21% 16% 3	2339
	21st to end	Night	46% 4 10% 21% 16% 4	1884
March	1st to 10th	Night	44% 4 9% 22% 18% 4	3490
	11th to 20th	Night	34% 5% 10% 25% 23% 4	3480
	21st to end	Night	53% 7% 11% 22% 6% 1	3756
April	1st to 10th	Night	35% 5% 11% 26% 19% 4	1900
	11th to 20th	Night	39% 5% 9% 24% 17% 6%	1875
	21st to end	Night	43% 5% 10% 23% 17% 1	1900
May	1st to 10th	Night	40% 9% 15% 20% 14% 2	2975
	11th to 20th	Night	39% 8% 13% 27% 12% 1	2645
	21st to end	Night	33% 9% 13% 24% 20% 2	2751
June	1st to 10th	Night	29% 7% 14% 30% 16% 3	1520
	11th to 20th	Night	26% 7% 10% 28% 24% 4	1520
	21st to end	Night	21% 6% 18% 28% 21% 7%	1520
July	1st to 10th	Night	36% 6% 10% 28% 17% 2	2490
	11th to 20th	Night	21% 7% 12% 39% 19% 2	2660
	21st to end	Night	29% 9% 19% 30% 13% 1	2999
August	1st to 10th	Night	19% 5% 21% 31% 22% 2	2826
	11th to 20th	Night	33% 6% 12% 28% 18% 3	2976
	21st to end	Night	22% 6% 17% 36% 15% 4	3476
September	1st to 10th	Night	29% 5% 11% 24% 25% 7%	1900
	11th to 20th	Night	29% 7% 10% 24% 24% 5%	1900
	21st to end	Night	30% 5% 8% 27% 27% 3	2159
October	1st to 10th	Night	25% 5% 9% 28% 29% 6%	2280
	11th to 20th	Night	34% 4 7% 26% 23% 7%	2280
	21st to end	Night	39% 3 9% 23% 22% 4	2508
November	1st to 10th	Night	30% 4 12% 28% 20% 6%	2329
	11th to 20th	Night	37% 3 7% 26% 22% 4	2470
	21st to end	Night	42% 4 10% 25% 17% 2	2659
December	1st to 10th	Night	45% 5% 12% 24% 13% 1	2660
	11th to 20th	Night	46% 4 9% 26% 13% 1	3281
	21st to end	Night	64% 4 9% 14% 8% 1	4884

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	27% 22% 34% 14% 3	270
	11th to 20th	Day	36% 18% 36% 9% 1	270
	21st to end	Day	23% 26% 37% 12% 3	297
February	1st to 10th	Day	30% 23% 32% 13% 2	270
	11th to 20th	Day	32% 21% 31% 13% 3	270
	21st to end	Day	33% 23% 34% 8% 2	225
March	1st to 10th	Day	20% 31% 38% 10% 1	270
	11th to 20th	Day	32% 20% 34% 13% 2	270
	21st to end	Day	38% 22% 28% 11% 1	332
April	1st to 10th	Day	23% 17% 37% 18% 5% 1	460
	11th to 20th	Day	30% 15% 32% 17% 5%	452
	21st to end	Day	28% 15% 34% 18% 4	460
May	1st to 10th	Day	21% 16% 38% 20% 6% 1	572
	11th to 20th	Day	20% 14% 28% 23% 13% 2	675
	21st to end	Day	15% 10% 35% 22% 14% 4	734
June	1st to 10th	Day	9% 4 28% 35% 18% 5%	680
	11th to 20th	Day	7% 5% 27% 41% 18% 2	680
	21st to end	Day	6% 9% 35% 35% 12% 4	680
July	1st to 10th	Day	12% 2 18% 31% 27% 9%	671
	11th to 20th	Day	6% 4 24% 36% 26% 4	668
	21st to end	Day	9% 4 18% 36% 27% 6%	739
August	1st to 10th	Day	8% 2 20% 41% 23% 5%	676
	11th to 20th	Day	10% 4 22% 35% 24% 5%	572
	21st to end	Day	9% 3 17% 31% 30% 9%	539
September	1st to 10th	Day	13% 4 16% 32% 28% 7%	490
	11th to 20th	Day	8% 4 20% 34% 25% 9%	490
	21st to end	Day	11% 11% 25% 35% 15% 3	340
October	1st to 10th	Day	13% 7% 34% 28% 13% 4	300
	11th to 20th	Day	21% 20% 32% 18% 8% 1	300
	21st to end	Day	33% 18% 31% 16% 2	330
November	1st to 10th	Day	17% 15% 37% 20% 9% 3	276
	11th to 20th	Day	26% 18% 29% 20% 6% 2	270
	21st to end	Day	30% 14% 29% 22% 4 1	270
December	1st to 10th	Day	21% 23% 34% 14% 6% 2	270
	11th to 20th	Day	24% 21% 35% 16% 3 1	270
	21st to end	Day	29% 25% 34% 11% 1	297
January	1st to 10th	Night	20% 18% 36% 21% 4 1	950
	11th to 20th	Night	25% 20% 34% 18% 4	950
	21st to end	Night	21% 18% 36% 23% 2	1045
February	1st to 10th	Night	23% 18% 37% 19% 2	950
	11th to 20th	Night	22% 19% 35% 22% 2	864
	21st to end	Night	27% 19% 35% 16% 3	628
March	1st to 10th	Night	24% 16% 38% 19% 3	619
	11th to 20th	Night	23% 14% 34% 26% 3	570
	21st to end	Night	28% 17% 32% 19% 3	627
April	1st to 10th	Night	18% 18% 36% 24% 4	570
	11th to 20th	Night	21% 14% 35% 25% 5%	563
	21st to end	Night	21% 12% 38% 23% 6%	570
May	1st to 10th	Night	17% 8% 34% 32% 8%	570
	11th to 20th	Night	16% 7% 30% 32% 14% 1	561
	21st to end	Night	13% 7% 29% 32% 19% 1	617
June	1st to 10th	Night	11% 3 19% 40% 25% 2	570
	11th to 20th	Night	7% 3 26% 42% 20% 1	570
	21st to end	Night	4 3 29% 45% 17% 2	570
July	1st to 10th	Night	12% 1 14% 36% 32% 5%	555
	11th to 20th	Night	4 2 18% 44% 31% 2	552
	21st to end	Night	6% 2 18% 40% 32% 2	624
August	1st to 10th	Night	8% 2 14% 43% 32% 1	567
	11th to 20th	Night	9% 3 14% 42% 30% 3	564
	21st to end	Night	7% 3 15% 37% 35% 3	627
September	1st to 10th	Night	12% 2 17% 38% 26% 5%	570
	11th to 20th	Night	11% 3 17% 37% 28% 4	570
	21st to end	Night	10% 6% 23% 36% 21% 4	683
October	1st to 10th	Night	10% 7% 27% 31% 22% 3	760
	11th to 20th	Night	16% 13% 34% 27% 9% 1	760
	21st to end	Night	23% 13% 33% 24% 7%	836
November	1st to 10th	Night	14% 12% 36% 28% 10%	749
	11th to 20th	Night	18% 17% 32% 26% 7%	760
	21st to end	Night	23% 14% 32% 24% 6%	949
December	1st to 10th	Night	22% 15% 35% 23% 5% 1	950
	11th to 20th	Night	25% 14% 31% 26% 4	950
	21st to end	Night	27% 18% 33% 20% 2	1045

Page generated at 2024-10-31 02:39:24. Version ac07

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