Springfield
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Springfield 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	12% 7% 3 6% 4 4 4 3 5% 7% 44%	100928
	Night	12% 7% 3 6% 4 3 4 3 5% 7% 48%	98177
Transparency	Day	37% 6% 12% 25% 17% 3	104578
	Night	35% 6% 11% 25% 19% 4	102667
Seeing	Day	15% 10% 27% 27% 17% 5%	15543
	Night	15% 11% 31% 30% 12% 1	25346

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	14% 12% 4 5% 4 3 3 2 4 4 45%	2847
	11th to 20th	Day	10% 11% 4 8% 5% 4 4 3 4 5% 42%	2850
	21st to end	Day	21% 11% 4 7% 3 3 3 2 4 5% 38%	3135
February	1st to 10th	Day	14% 12% 4 8% 5% 4 4 3 4 5% 36%	1710
	11th to 20th	Day	14% 9% 4 8% 5% 3 3 3 4 5% 42%	1687
	21st to end	Day	16% 10% 3 6% 5% 5% 4 3 4 7% 38%	1641
March	1st to 10th	Day	15% 9% 3 5% 3 3 3 3 4 5% 47%	3436
	11th to 20th	Day	13% 8% 2 4 3 3 3 3 4 6% 50%	3480
	21st to end	Day	16% 10% 4 7% 5% 5% 4 3 5% 6% 34%	3814
April	1st to 10th	Day	11% 8% 3 6% 4 3 4 4 5% 6% 45%	2251
	11th to 20th	Day	16% 9% 3 5% 4 4 4 4 6% 6% 40%	2254
	21st to end	Day	20% 8% 3 6% 4 5% 4 3 5% 7% 36%	2280
May	1st to 10th	Day	19% 8% 3 6% 4 4 5% 3 6% 7% 36%	4014
	11th to 20th	Day	14% 6% 2 6% 4 5% 4 4 6% 7% 41%	4082
	21st to end	Day	14% 6% 2 6% 5% 5% 5% 4 7% 8% 40%	4631
June	1st to 10th	Day	9% 4 2 6% 4 4 5% 4 6% 11% 46%	2660
	11th to 20th	Day	7% 4 1 5% 4 5% 6% 4 7% 10% 47%	2660
	21st to end	Day	5% 3 1 5% 4 4 4 4 7% 9% 54%	2660
July	1st to 10th	Day	11% 6% 2 6% 5% 5% 5% 4 7% 9% 41%	4127
	11th to 20th	Day	5% 4 2 6% 4 5% 5% 5% 7% 10% 46%	4120
	21st to end	Day	7% 5% 2 6% 5% 5% 6% 5% 8% 12% 39%	4465
August	1st to 10th	Day	5% 3 2 5% 4 4 4 3 5% 9% 56%	4104
	11th to 20th	Day	10% 5% 2 6% 5% 4 5% 4 7% 8% 44%	3927
	21st to end	Day	5% 4 1 5% 4 4 4 4 6% 8% 54%	4180
September	1st to 10th	Day	11% 5% 2 5% 4 5% 4 3 4 7% 50%	2280
	11th to 20th	Day	11% 5% 3 6% 4 5% 5% 4 5% 7% 46%	2217
	21st to end	Day	7% 5% 2 5% 4 4 5% 4 6% 7% 52%	2014
October	1st to 10th	Day	10% 4 1 4 3 3 3 3 5% 6% 57%	1900
	11th to 20th	Day	13% 7% 2 5% 3 2 3 3 3 5% 55%	1900
	21st to end	Day	18% 6% 2 5% 3 3 3 2 5% 5% 48%	2090
November	1st to 10th	Day	12% 5% 2 4 3 3 2 3 4 4 57%	1898
	11th to 20th	Day	14% 8% 3 5% 3 3 3 3 5% 6% 49%	1763
	21st to end	Day	15% 9% 3 5% 4 3 3 1 4 6% 48%	1520
December	1st to 10th	Day	12% 10% 3 6% 4 4 3 3 5% 7% 43%	1520
	11th to 20th	Day	12% 11% 3 8% 5% 4 3 3 3 5% 42%	1918
	21st to end	Day	14% 16% 7% 9% 5% 4 4 3 4 5% 28%	2893
January	1st to 10th	Night	12% 10% 4 9% 4 4 4 3 4 5% 42%	4108
	11th to 20th	Night	11% 6% 3 8% 8% 4 5% 4 5% 5% 42%	4120
	21st to end	Night	20% 13% 5% 6% 3 2 2 2 3 4 39%	4532
February	1st to 10th	Night	14% 10% 4 6% 4 3 4 3 5% 5% 43%	2470
	11th to 20th	Night	15% 8% 3 7% 4 3 3 3 5% 6% 44%	2380
	21st to end	Night	14% 9% 4 6% 4 3 3 3 5% 5% 44%	1827
March	1st to 10th	Night	16% 10% 2 6% 3 3 2 2 4 5% 46%	3419
	11th to 20th	Night	12% 6% 2 5% 3 3 3 3 4 6% 51%	3480
	21st to end	Night	13% 9% 4 7% 5% 5% 4 4 5% 7% 38%	3817
April	1st to 10th	Night	10% 6% 2 4 4 3 3 3 5% 8% 52%	1929
	11th to 20th	Night	12% 8% 3 6% 3 3 3 3 6% 7% 46%	1875
	21st to end	Night	19% 7% 3 6% 4 3 3 4 6% 6% 39%	1900
May	1st to 10th	Night	14% 7% 3 5% 4 4 3 3 5% 7% 44%	2884
	11th to 20th	Night	14% 8% 2 6% 4 4 4 4 5% 8% 41%	2823
	21st to end	Night	13% 6% 3 6% 4 4 4 4 7% 9% 41%	2931
June	1st to 10th	Night	8% 4 2 4 3 3 4 4 6% 9% 52%	1520
	11th to 20th	Night	5% 4 1 4 4 4 4 4 7% 10% 54%	1520
	21st to end	Night	3 3 1 3 4 3 3 3 6% 8% 64%	1520
July	1st to 10th	Night	10% 5% 2 5% 4 4 4 4 6% 7% 48%	2837
	11th to 20th	Night	4 3 1 4 3 3 4 4 6% 9% 60%	2850
	21st to end	Night	6% 5% 2 5% 3 4 4 4 7% 10% 49%	3098
August	1st to 10th	Night	4 2 1 4 3 3 4 3 5% 9% 62%	2836
	11th to 20th	Night	9% 4 3 6% 4 4 5% 3 6% 7% 50%	2905
	21st to end	Night	4 3 1 4 3 3 4 3 5% 9% 61%	3476
September	1st to 10th	Night	9% 4 2 4 4 4 3 3 4 7% 56%	1900
	11th to 20th	Night	9% 5% 2 5% 3 3 4 3 6% 7% 53%	1959
	21st to end	Night	9% 5% 2 4 3 2 3 3 4 6% 58%	2147
October	1st to 10th	Night	7% 4 2 3 3 3 3 3 5% 7% 61%	2280
	11th to 20th	Night	12% 6% 2 3 3 3 3 3 4 5% 56%	2280
	21st to end	Night	16% 8% 2 5% 3 3 3 3 4 5% 50%	2508
November	1st to 10th	Night	12% 6% 2 4 2 2 3 2 3 6% 58%	2280
	11th to 20th	Night	11% 7% 2 6% 3 3 3 2 4 6% 53%	2411
	21st to end	Night	14% 9% 3 5% 4 3 3 3 4 5% 48%	2660
December	1st to 10th	Night	14% 10% 3 6% 2 3 3 3 5% 7% 42%	2660
	11th to 20th	Night	14% 9% 4 9% 4 3 3 3 4 5% 41%	3279
	21st to end	Night	17% 17% 6% 8% 4 3 3 3 4 5% 30%	4756

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	44% 4 7% 26% 17% 1	2848
	11th to 20th	Day	43% 5% 9% 27% 12% 3	2850
	21st to end	Day	49% 4 9% 17% 16% 4	3135
February	1st to 10th	Day	50% 5% 10% 22% 12% 2	1710
	11th to 20th	Day	45% 4 10% 21% 16% 4	1696
	21st to end	Day	47% 4 7% 20% 15% 7%	1641
March	1st to 10th	Day	40% 5% 8% 20% 19% 8%	3436
	11th to 20th	Day	35% 5% 10% 28% 15% 7%	3480
	21st to end	Day	49% 8% 12% 21% 9% 1	3814
April	1st to 10th	Day	39% 7% 12% 22% 19% 2	2251
	11th to 20th	Day	44% 6% 13% 18% 15% 3	2254
	21st to end	Day	49% 6% 10% 23% 11% 1	2280
May	1st to 10th	Day	47% 9% 12% 19% 13% 1	4051
	11th to 20th	Day	40% 9% 14% 24% 12%	4086
	21st to end	Day	39% 11% 13% 24% 13% 1	4644
June	1st to 10th	Day	32% 9% 16% 27% 15% 2	2660
	11th to 20th	Day	30% 8% 15% 31% 14% 2	2660
	21st to end	Day	25% 9% 16% 30% 16% 4	2660
July	1st to 10th	Day	37% 8% 16% 24% 13% 2	4063
	11th to 20th	Day	30% 8% 12% 32% 16% 2	4051
	21st to end	Day	35% 9% 21% 25% 9%	4325
August	1st to 10th	Day	25% 7% 18% 28% 22% 1	4090
	11th to 20th	Day	36% 7% 15% 28% 14% 1	3966
	21st to end	Day	27% 6% 12% 34% 17% 4	4179
September	1st to 10th	Day	34% 6% 12% 24% 15% 9%	2280
	11th to 20th	Day	37% 6% 9% 22% 24% 2	2217
	21st to end	Day	30% 7% 10% 26% 24% 4	2014
October	1st to 10th	Day	17% 3 6% 18% 37% 19%	3160
	11th to 20th	Day	22% 3 5% 23% 34% 14%	3140
	21st to end	Day	28% 3 8% 32% 24% 4	3428
November	1st to 10th	Day	31% 5% 9% 27% 22% 5%	1898
	11th to 20th	Day	36% 4 8% 21% 24% 6%	1763
	21st to end	Day	40% 4 9% 23% 21% 2	1520
December	1st to 10th	Day	42% 4 9% 29% 14% 2	1520
	11th to 20th	Day	45% 5% 7% 18% 23% 2	1915
	21st to end	Day	57% 6% 8% 16% 11% 1	2893
January	1st to 10th	Night	46% 4 10% 23% 15% 2	4108
	11th to 20th	Night	43% 6% 11% 25% 13% 2	4120
	21st to end	Night	50% 4 9% 20% 15% 2	4532
February	1st to 10th	Night	43% 5% 11% 23% 14% 3	2470
	11th to 20th	Night	42% 4 10% 22% 18% 4	2381
	21st to end	Night	43% 4 10% 21% 17% 6%	1827
March	1st to 10th	Night	41% 6% 9% 19% 19% 6%	3419
	11th to 20th	Night	35% 7% 10% 25% 21% 3	3480
	21st to end	Night	44% 8% 14% 23% 10% 1	3817
April	1st to 10th	Night	31% 6% 11% 25% 22% 5%	1929
	11th to 20th	Night	36% 6% 12% 22% 19% 5%	1875
	21st to end	Night	44% 6% 11% 22% 15% 1	1900
May	1st to 10th	Night	39% 7% 13% 23% 15% 3	2912
	11th to 20th	Night	39% 9% 13% 25% 12% 1	2824
	21st to end	Night	37% 10% 15% 26% 11%	2939
June	1st to 10th	Night	26% 7% 16% 29% 18% 3	1520
	11th to 20th	Night	23% 8% 15% 31% 21% 3	1520
	21st to end	Night	18% 5% 20% 31% 20% 6%	1520
July	1st to 10th	Night	33% 7% 16% 24% 15% 4	2792
	11th to 20th	Night	21% 6% 11% 38% 23% 1	2796
	21st to end	Night	27% 7% 21% 32% 12%	2999
August	1st to 10th	Night	19% 7% 15% 33% 24% 2	2826
	11th to 20th	Night	33% 6% 14% 29% 17% 1	2932
	21st to end	Night	20% 5% 14% 37% 19% 4	3476
September	1st to 10th	Night	28% 5% 13% 27% 19% 8%	1900
	11th to 20th	Night	30% 6% 11% 24% 26% 4	1959
	21st to end	Night	28% 4 10% 25% 30% 4	2147
October	1st to 10th	Night	14% 4 6% 16% 41% 18%	3800
	11th to 20th	Night	22% 2 6% 20% 31% 19%	3779
	21st to end	Night	30% 3 6% 31% 25% 5%	4120
November	1st to 10th	Night	29% 4 10% 26% 24% 7%	2280
	11th to 20th	Night	33% 4 7% 25% 25% 6%	2411
	21st to end	Night	39% 4 8% 24% 22% 3	2660
December	1st to 10th	Night	42% 5% 11% 23% 18% 2	2660
	11th to 20th	Night	46% 4 7% 21% 20% 2	3281
	21st to end	Night	56% 6% 10% 16% 9% 2	4756

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	21% 19% 39% 18% 3	270
	11th to 20th	Day	25% 23% 37% 14% 1	270
	21st to end	Day	19% 20% 43% 15% 3	297
February	1st to 10th	Day	21% 19% 43% 15% 2	270
	11th to 20th	Day	24% 26% 31% 16% 2	270
	21st to end	Day	28% 24% 36% 10% 1	225
March	1st to 10th	Day	22% 23% 34% 20% 2	270
	11th to 20th	Day	26% 17% 34% 20% 3	270
	21st to end	Day	27% 21% 39% 10% 2 1	297
April	1st to 10th	Day	21% 16% 39% 20% 4	431
	11th to 20th	Day	22% 17% 37% 18% 5%	452
	21st to end	Day	24% 17% 31% 21% 6% 1	460
May	1st to 10th	Day	21% 13% 33% 25% 7% 1	610
	11th to 20th	Day	16% 10% 30% 27% 14% 3	675
	21st to end	Day	13% 8% 32% 26% 15% 6%	734
June	1st to 10th	Day	10% 4 20% 31% 27% 8%	680
	11th to 20th	Day	7% 3 19% 38% 28% 5%	680
	21st to end	Day	6% 2 29% 36% 22% 5%	680
July	1st to 10th	Day	10% 3 16% 29% 30% 11%	671
	11th to 20th	Day	5% 4 14% 37% 31% 9%	668
	21st to end	Day	9% 2 12% 35% 29% 13%	739
August	1st to 10th	Day	8% 4 12% 41% 29% 5%	676
	11th to 20th	Day	10% 2 16% 35% 30% 7%	603
	21st to end	Day	11% 1 11% 29% 37% 12%	539
September	1st to 10th	Day	12% 1 10% 37% 30% 10%	490
	11th to 20th	Day	10% 2 18% 37% 24% 10%	427
	21st to end	Day	10% 5% 27% 30% 21% 7%	300
October	1st to 10th	Day	10% 8% 26% 33% 19% 4	300
	11th to 20th	Day	14% 15% 35% 25% 9% 1	300
	21st to end	Day	26% 15% 30% 25% 3 1	330
November	1st to 10th	Day	15% 13% 38% 23% 9% 2	282
	11th to 20th	Day	16% 21% 30% 24% 7% 1	270
	21st to end	Day	22% 17% 34% 21% 5% 1	270
December	1st to 10th	Day	16% 14% 44% 17% 6% 3	270
	11th to 20th	Day	21% 17% 39% 19% 5%	270
	21st to end	Day	18% 27% 38% 14% 2	297
January	1st to 10th	Night	17% 19% 38% 22% 5%	950
	11th to 20th	Night	19% 19% 41% 17% 4	950
	21st to end	Night	17% 18% 42% 21% 2	1045
February	1st to 10th	Night	19% 16% 44% 19% 3	950
	11th to 20th	Night	21% 17% 41% 20% 2	906
	21st to end	Night	21% 22% 38% 17% 2	571
March	1st to 10th	Night	19% 16% 37% 24% 4	570
	11th to 20th	Night	22% 15% 34% 24% 5%	570
	21st to end	Night	21% 17% 36% 21% 4	627
April	1st to 10th	Night	14% 16% 39% 28% 4	570
	11th to 20th	Night	17% 13% 39% 26% 5%	563
	21st to end	Night	22% 12% 36% 22% 8%	570
May	1st to 10th	Night	16% 6% 38% 32% 8%	570
	11th to 20th	Night	14% 6% 29% 33% 17% 1	561
	21st to end	Night	12% 5% 31% 31% 19% 2	617
June	1st to 10th	Night	8% 4 17% 42% 28% 1	570
	11th to 20th	Night	5% 2 24% 46% 22% 1	570
	21st to end	Night	2 2 23% 49% 23% 1	570
July	1st to 10th	Night	8% 1 11% 41% 33% 5%	555
	11th to 20th	Night	3 1 11% 46% 35% 4	552
	21st to end	Night	6% 1 9% 47% 33% 4	624
August	1st to 10th	Night	7% 2 10% 49% 30% 3	567
	11th to 20th	Night	9% 2 13% 49% 24% 3	564
	21st to end	Night	5% 1 13% 41% 36% 4	627
September	1st to 10th	Night	10% 2 15% 41% 30% 3	570
	11th to 20th	Night	11% 2 14% 43% 26% 3	570
	21st to end	Night	12% 4 22% 40% 20% 3	627
October	1st to 10th	Night	8% 4 28% 35% 21% 3	760
	11th to 20th	Night	16% 8% 36% 31% 8%	760
	21st to end	Night	21% 11% 31% 28% 9%	836
November	1st to 10th	Night	14% 11% 38% 28% 9%	760
	11th to 20th	Night	15% 14% 38% 26% 7%	779
	21st to end	Night	20% 13% 36% 24% 7%	950
December	1st to 10th	Night	21% 13% 39% 23% 5%	950
	11th to 20th	Night	22% 14% 36% 25% 3	950
	21st to end	Night	20% 18% 40% 21% 2	1045

Page generated at 2024-11-03 01:11:22. Version ac07

Copyright © 2024 Attilla Danko.