Mantese's Farm
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mantese's Farm clear sky chart from 2005-11-06 to 2024-11-30.

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 6% 8% 42%	101413
	Night	13% 8% 3 6% 4 4 4 3 5% 7% 43%	98230
Transparency	Day	37% 6% 12% 25% 17% 3	105032
	Night	38% 6% 11% 24% 18% 3	102752
Seeing	Day	14% 8% 23% 27% 20% 8%	15687
	Night	16% 7% 27% 33% 15% 2	25516

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	11% 10% 5% 9% 5% 5% 5% 4 6% 7% 32%	2527
	11th to 20th	Day	13% 9% 3 7% 5% 6% 5% 5% 6% 8% 34%	2704
	21st to end	Day	21% 17% 5% 6% 4 3 3 3 4 5% 29%	3135
February	1st to 10th	Day	16% 11% 4 8% 4 4 4 4 4 7% 35%	1714
	11th to 20th	Day	16% 9% 3 7% 5% 3 5% 3 5% 6% 38%	1848
	21st to end	Day	14% 10% 2 8% 5% 4 4 3 5% 7% 39%	1570
March	1st to 10th	Day	18% 11% 3 7% 4 3 3 3 4 4 40%	3138
	11th to 20th	Day	13% 8% 2 4 4 3 4 3 5% 6% 49%	3480
	21st to end	Day	14% 8% 3 7% 5% 4 4 5% 6% 8% 36%	4037
April	1st to 10th	Day	11% 6% 2 7% 5% 4 4 4 6% 7% 42%	2280
	11th to 20th	Day	15% 8% 3 6% 5% 4 4 3 5% 6% 42%	2254
	21st to end	Day	17% 7% 3 7% 5% 4 5% 4 5% 7% 37%	2280
May	1st to 10th	Day	13% 6% 3 8% 5% 4 6% 5% 8% 10% 32%	3883
	11th to 20th	Day	16% 8% 3 7% 4 4 4 3 5% 7% 39%	4297
	21st to end	Day	10% 6% 2 7% 5% 5% 5% 4 5% 8% 44%	4824
June	1st to 10th	Day	8% 5% 2 6% 4 4 5% 4 7% 9% 46%	2660
	11th to 20th	Day	7% 4 2 4 4 4 4 4 7% 10% 50%	2660
	21st to end	Day	4 4 2 6% 5% 4 5% 5% 7% 11% 48%	2660
July	1st to 10th	Day	12% 5% 2 5% 4 4 5% 5% 7% 9% 42%	4440
	11th to 20th	Day	4 4 2 5% 4 5% 5% 5% 7% 12% 47%	4440
	21st to end	Day	6% 6% 2 8% 5% 5% 6% 5% 8% 10% 40%	4602
August	1st to 10th	Day	4 4 2 5% 4 4 5% 4 7% 9% 52%	4045
	11th to 20th	Day	12% 6% 2 5% 4 5% 4 4 7% 10% 42%	3729
	21st to end	Day	6% 4 2 5% 4 4 4 4 6% 9% 51%	4180
September	1st to 10th	Day	13% 5% 2 4 4 4 4 4 5% 7% 48%	2280
	11th to 20th	Day	9% 5% 2 5% 5% 4 4 3 6% 7% 49%	2242
	21st to end	Day	8% 4 2 5% 4 4 4 4 6% 8% 51%	2090
October	1st to 10th	Day	9% 4 2 5% 3 3 4 2 4 6% 56%	1919
	11th to 20th	Day	12% 5% 2 4 4 3 3 2 5% 6% 52%	1900
	21st to end	Day	16% 8% 2 5% 3 2 3 3 4 5% 47%	2057
November	1st to 10th	Day	10% 6% 2 4 4 3 3 3 5% 6% 54%	1762
	11th to 20th	Day	14% 7% 2 6% 4 3 4 3 5% 8% 45%	1800
	21st to end	Day	15% 10% 3 6% 5% 3 4 3 4 5% 42%	1755
December	1st to 10th	Day	14% 11% 3 6% 5% 3 4 4 5% 7% 39%	1520
	11th to 20th	Day	14% 10% 3 8% 5% 4 4 4 5% 6% 38%	1918
	21st to end	Day	20% 13% 5% 8% 5% 5% 5% 3 4 5% 27%	2783
January	1st to 10th	Night	15% 9% 4 8% 5% 5% 5% 4 5% 5% 36%	4428
	11th to 20th	Night	13% 11% 4 9% 6% 7% 6% 3 5% 5% 31%	4248
	21st to end	Night	24% 15% 4 7% 4 3 3 3 4 6% 28%	4532
February	1st to 10th	Night	16% 11% 5% 8% 5% 3 4 3 5% 4 36%	2464
	11th to 20th	Night	14% 8% 3 7% 5% 4 3 3 5% 6% 42%	2218
	21st to end	Night	16% 9% 3 8% 4 4 4 3 5% 5% 39%	1884
March	1st to 10th	Night	20% 10% 2 5% 4 4 3 3 4 4 42%	3733
	11th to 20th	Night	13% 7% 2 5% 3 3 3 3 4 6% 51%	3490
	21st to end	Night	16% 9% 4 7% 6% 5% 4 4 5% 6% 35%	3580
April	1st to 10th	Night	11% 6% 2 7% 4 3 4 4 5% 6% 48%	1900
	11th to 20th	Night	13% 7% 2 5% 4 5% 4 4 5% 7% 45%	1875
	21st to end	Night	19% 8% 3 6% 5% 2 3 4 4 5% 42%	1900
May	1st to 10th	Night	16% 7% 2 5% 4 4 5% 4 6% 8% 39%	3010
	11th to 20th	Night	14% 8% 2 5% 4 3 4 4 4 7% 45%	2601
	21st to end	Night	9% 6% 3 7% 5% 5% 5% 5% 7% 9% 41%	2743
June	1st to 10th	Night	7% 4 2 6% 4 4 5% 4 7% 9% 48%	1520
	11th to 20th	Night	5% 4 2 5% 3 3 4 5% 6% 10% 55%	1520
	21st to end	Night	4 4 1 4 3 4 5% 4 8% 10% 53%	1520
July	1st to 10th	Night	12% 4 2 5% 4 3 4 3 6% 10% 47%	2530
	11th to 20th	Night	5% 4 2 5% 3 4 4 3 6% 9% 56%	2530
	21st to end	Night	7% 6% 2 8% 6% 5% 6% 5% 7% 11% 38%	2958
August	1st to 10th	Night	4 3 1 4 3 4 4 4 6% 9% 57%	2889
	11th to 20th	Night	9% 5% 2 6% 4 4 5% 4 6% 8% 45%	3100
	21st to end	Night	5% 3 1 4 3 3 4 3 6% 9% 58%	3476
September	1st to 10th	Night	11% 5% 2 4 4 3 4 3 5% 7% 53%	1900
	11th to 20th	Night	8% 5% 2 5% 4 4 5% 3 6% 7% 51%	1919
	21st to end	Night	10% 4 2 4 4 4 4 3 6% 7% 53%	2090
October	1st to 10th	Night	7% 4 2 5% 3 3 3 3 4 7% 59%	2256
	11th to 20th	Night	12% 6% 2 5% 3 2 3 2 4 7% 54%	2280
	21st to end	Night	18% 6% 2 4 3 3 4 2 4 6% 47%	2539
November	1st to 10th	Night	11% 5% 1 5% 3 3 3 3 4 4 57%	2536
	11th to 20th	Night	14% 5% 2 5% 4 4 3 3 4 6% 49%	2600
	21st to end	Night	17% 9% 4 4 4 2 3 3 4 6% 44%	2638
December	1st to 10th	Night	16% 11% 4 6% 4 4 3 3 6% 7% 36%	2660
	11th to 20th	Night	16% 8% 3 6% 4 4 4 3 4 5% 41%	3279
	21st to end	Night	17% 16% 5% 10% 6% 5% 5% 4 5% 5% 24%	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	48% 6% 12% 24% 8% 1	2528
	11th to 20th	Day	44% 7% 13% 22% 13%	2704
	21st to end	Day	57% 5% 9% 16% 11% 1	3135
February	1st to 10th	Day	49% 4 12% 23% 11% 1	1714
	11th to 20th	Day	48% 5% 10% 20% 14% 3	1858
	21st to end	Day	45% 5% 10% 22% 14% 3	1570
March	1st to 10th	Day	48% 4 7% 21% 16% 4	3138
	11th to 20th	Day	36% 5% 10% 26% 17% 5%	3480
	21st to end	Day	43% 8% 17% 22% 9% 1	4037
April	1st to 10th	Day	38% 6% 12% 26% 17% 1	2280
	11th to 20th	Day	43% 5% 10% 24% 15% 3	2254
	21st to end	Day	46% 6% 12% 22% 12% 1	2280
May	1st to 10th	Day	42% 10% 15% 23% 9% 1	3918
	11th to 20th	Day	44% 8% 11% 25% 12% 1	4301
	21st to end	Day	36% 9% 11% 22% 21% 1	4837
June	1st to 10th	Day	33% 8% 13% 27% 17% 3	2660
	11th to 20th	Day	27% 7% 13% 26% 24% 3	2660
	21st to end	Day	28% 9% 17% 25% 16% 6%	2660
July	1st to 10th	Day	36% 7% 11% 30% 13% 2	4371
	11th to 20th	Day	27% 8% 15% 31% 17% 2	4365
	21st to end	Day	35% 11% 16% 26% 11% 1	4457
August	1st to 10th	Day	25% 8% 15% 37% 15%	4031
	11th to 20th	Day	36% 7% 14% 25% 17% 1	3765
	21st to end	Day	28% 6% 14% 34% 15% 3	4179
September	1st to 10th	Day	34% 7% 10% 25% 20% 5%	2280
	11th to 20th	Day	34% 6% 9% 25% 24% 3	2242
	21st to end	Day	30% 6% 9% 27% 24% 3	2090
October	1st to 10th	Day	18% 3 5% 21% 44% 9%	3192
	11th to 20th	Day	23% 3 8% 21% 37% 9%	3140
	21st to end	Day	31% 3 7% 27% 28% 3	3371
November	1st to 10th	Day	31% 4 13% 26% 20% 6%	1762
	11th to 20th	Day	38% 5% 8% 24% 20% 6%	1800
	21st to end	Day	45% 4 9% 26% 15% 1	1755
December	1st to 10th	Day	43% 7% 12% 25% 13% 1	1520
	11th to 20th	Day	47% 5% 10% 22% 14% 2	1915
	21st to end	Day	58% 6% 10% 16% 8% 2	2783
January	1st to 10th	Night	48% 6% 11% 24% 10% 1	4428
	11th to 20th	Night	53% 6% 9% 21% 10% 1	4248
	21st to end	Night	58% 4 10% 19% 8% 1	4532
February	1st to 10th	Night	51% 5% 9% 21% 12% 1	2464
	11th to 20th	Night	43% 4 11% 22% 18% 2	2219
	21st to end	Night	47% 4 11% 21% 14% 4	1884
March	1st to 10th	Night	46% 5% 8% 23% 16% 2	3733
	11th to 20th	Night	34% 5% 12% 24% 21% 4	3490
	21st to end	Night	48% 8% 11% 25% 8% 1	3580
April	1st to 10th	Night	35% 5% 12% 27% 17% 3	1900
	11th to 20th	Night	38% 5% 11% 23% 19% 4	1875
	21st to end	Night	45% 5% 8% 24% 16% 2	1900
May	1st to 10th	Night	41% 9% 16% 20% 13% 1	3040
	11th to 20th	Night	38% 7% 14% 26% 14% 1	2602
	21st to end	Night	36% 10% 12% 24% 16% 2	2751
June	1st to 10th	Night	30% 8% 14% 26% 18% 4	1520
	11th to 20th	Night	23% 6% 13% 28% 25% 4	1520
	21st to end	Night	24% 8% 14% 28% 18% 7%	1520
July	1st to 10th	Night	33% 6% 12% 29% 16% 4	2490
	11th to 20th	Night	23% 7% 11% 37% 19% 3	2482
	21st to end	Night	36% 9% 17% 24% 13% 2	2864
August	1st to 10th	Night	21% 7% 16% 35% 19% 1	2879
	11th to 20th	Night	34% 7% 12% 24% 20% 2	3130
	21st to end	Night	22% 6% 14% 35% 19% 3	3476
September	1st to 10th	Night	31% 5% 10% 26% 21% 7%	1900
	11th to 20th	Night	31% 6% 9% 25% 25% 5%	1919
	21st to end	Night	29% 7% 9% 23% 27% 5%	2090
October	1st to 10th	Night	16% 3 6% 17% 49% 9%	3763
	11th to 20th	Night	21% 3 7% 21% 39% 8%	3779
	21st to end	Night	31% 4 9% 24% 26% 6%	4175
November	1st to 10th	Night	31% 4 12% 25% 23% 6%	2536
	11th to 20th	Night	36% 3 8% 24% 24% 5%	2600
	21st to end	Night	42% 4 10% 25% 18% 2	2638
December	1st to 10th	Night	47% 5% 10% 23% 13% 1	2660
	11th to 20th	Night	44% 5% 10% 24% 16% 1	3281
	21st to end	Night	59% 7% 10% 15% 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	21% 15% 31% 23% 9% 1	270
	11th to 20th	Day	24% 15% 39% 19% 3	270
	21st to end	Day	19% 15% 43% 16% 7%	297
February	1st to 10th	Day	21% 14% 39% 20% 6%	270
	11th to 20th	Day	24% 14% 35% 19% 6% 1	270
	21st to end	Day	22% 16% 33% 24% 4	225
March	1st to 10th	Day	18% 14% 44% 19% 5%	270
	11th to 20th	Day	27% 11% 38% 17% 5% 2	270
	21st to end	Day	26% 15% 30% 22% 7% 1	430
April	1st to 10th	Day	16% 12% 36% 25% 10% 2	460
	11th to 20th	Day	20% 13% 30% 24% 13% 1	452
	21st to end	Day	21% 12% 32% 21% 13% 1	460
May	1st to 10th	Day	14% 13% 26% 30% 14% 2	463
	11th to 20th	Day	17% 9% 23% 25% 20% 7%	612
	21st to end	Day	11% 4 25% 33% 19% 9%	734
June	1st to 10th	Day	11% 4 18% 29% 27% 12%	680
	11th to 20th	Day	8% 1 18% 35% 28% 10%	680
	21st to end	Day	4 4 23% 37% 23% 10%	680
July	1st to 10th	Day	11% 3 11% 25% 28% 22%	671
	11th to 20th	Day	5% 2 10% 36% 32% 14%	668
	21st to end	Day	9% 2 11% 30% 36% 12%	739
August	1st to 10th	Day	7% 2 9% 33% 35% 13%	643
	11th to 20th	Day	11% 4 12% 25% 35% 13%	479
	21st to end	Day	10% 2 8% 24% 36% 20%	539
September	1st to 10th	Day	14% 2 13% 22% 34% 15%	490
	11th to 20th	Day	9% 1 9% 27% 35% 19%	490
	21st to end	Day	10% 7% 19% 28% 25% 12%	490
October	1st to 10th	Day	11% 4 21% 33% 21% 10%	319
	11th to 20th	Day	12% 13% 33% 27% 12% 4	300
	21st to end	Day	24% 15% 27% 23% 10%	330
November	1st to 10th	Day	12% 8% 33% 27% 16% 5%	300
	11th to 20th	Day	15% 18% 31% 20% 15% 2	300
	21st to end	Day	24% 12% 30% 22% 10% 2	299
December	1st to 10th	Day	13% 15% 37% 21% 8% 6%	270
	11th to 20th	Day	22% 12% 34% 23% 8% 1	270
	21st to end	Day	25% 15% 38% 18% 4	297
January	1st to 10th	Night	19% 11% 38% 26% 5%	950
	11th to 20th	Night	20% 13% 38% 24% 5%	950
	21st to end	Night	18% 11% 40% 29% 2	1045
February	1st to 10th	Night	21% 12% 35% 28% 3	944
	11th to 20th	Night	18% 14% 39% 28% 1	743
	21st to end	Night	20% 11% 41% 27% 1	628
March	1st to 10th	Night	21% 11% 37% 28% 4	760
	11th to 20th	Night	21% 9% 35% 30% 5%	580
	21st to end	Night	22% 8% 31% 33% 6%	627
April	1st to 10th	Night	14% 10% 39% 29% 8%	570
	11th to 20th	Night	17% 8% 31% 30% 13% 1	563
	21st to end	Night	23% 6% 34% 29% 8% 1	570
May	1st to 10th	Night	16% 5% 28% 38% 11% 1	570
	11th to 20th	Night	17% 4 23% 35% 19% 2	561
	21st to end	Night	10% 4 18% 43% 22% 4	617
June	1st to 10th	Night	9% 1 18% 41% 28% 2	570
	11th to 20th	Night	5% 16% 51% 26% 2	570
	21st to end	Night	5% 2 19% 42% 30% 2	570
July	1st to 10th	Night	9% 2 8% 36% 38% 6%	555
	11th to 20th	Night	5% 1 10% 41% 39% 4	552
	21st to end	Night	7% 2 11% 39% 38% 3	624
August	1st to 10th	Night	7% 2 7% 41% 40% 3	567
	11th to 20th	Night	7% 1 10% 41% 37% 4	564
	21st to end	Night	7% 2 7% 36% 42% 6%	627
September	1st to 10th	Night	12% 3 9% 37% 33% 5%	570
	11th to 20th	Night	9% 2 11% 38% 34% 6%	589
	21st to end	Night	11% 5% 19% 33% 29% 4	760
October	1st to 10th	Night	8% 3 21% 36% 26% 5%	760
	11th to 20th	Night	15% 6% 31% 32% 15% 1	760
	21st to end	Night	21% 8% 31% 32% 8%	836
November	1st to 10th	Night	13% 5% 33% 37% 11%	780
	11th to 20th	Night	16% 9% 34% 31% 9% 1	800
	21st to end	Night	22% 9% 33% 29% 7%	839
December	1st to 10th	Night	21% 10% 31% 32% 6% 1	950
	11th to 20th	Night	22% 7% 29% 34% 7%	950
	21st to end	Night	22% 12% 36% 27% 4	1045

Page generated at 2024-11-27 16:30:49. Version ac07

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