Frequently Asked Questions

No, you don't need an account for basic use. Guest charts allow you to:

• Search for weather stations
• Create temporary GDD charts
• View current season data compared to a preselected previous season
• Generate chart image sharing links

However, creating a free beta account gives you:

• Saved charts you can access anytime
• Multiple locations and charts
• Custom season start and end dates
• Various base temperatures and calculation methods
• Threshold alerts and notifications
• Historical comparisons and advanced features

Yes, GDD-Pro is currently free during beta. You have full access to all features while we gather feedback and improve the platform.

After beta, we plan to offer:

• Free tier: Basic GDD calculation and visualization
• Premium features: Advanced analysis, alerts, and additional limits

Our goal is to keep core GDD tracking accessible to everyone in agriculture.

Guest Users:

1. Use the station search feature on the homepage
2. Enter an address, city, or ZIP code
3. Review the list of nearby stations with distances
4. Choose the closest station with current data

Signed in users:

1. Navigate to My Dashboard
2. Click "Create Location"
3. Enter a location name and find nearby weather stations
4. Choose the closest station with current data

For logged-in users:

1. Navigate to My Dashboard
2. Click "Create Location"
3. Enter a location name and find nearby weather stations
4. Choose the closest station with current data
5. Click "Create Chart" within your location
6. Configure your chart: Set base temperature (e.g., 50°F for corn), start date, and end date
7. Save to view your GDD accumulation

Your chart will show cumulative GDD from your start date through the current season.

Growing Degree Days (GDD) measure accumulated heat units above a minimum temperature threshold. Plants require a certain amount of heat to progress through growth stages.

The basic formula:

GDD = (T_max + T_min) / 2 − T_base

For example, with a high of 75°F, low of 55°F, and base temp of 50°F:

GDD = (75 + 55) / 2 − 50 = 15 GDD

These values accumulate daily throughout the growing season to help predict crop development stages, pest emergence, and optimal timing for agricultural operations.

Base temperature varies by crop. Here are common values:

• 50°F: Corn, soybeans, sorghum, cotton
• 40°F: Wheat, barley, oats, peas, canola
• 45°F: Potatoes, alfalfa
• 32°F: Cool-season vegetables (spinach, lettuce, cabbage)
• 60°F: Warm-season vegetables (melons, peppers)

Modified GDD (MGDD) adds an optional maximum temperature cap to the standard GDD calculation. Above this threshold, additional heat doesn't accelerate plant growth and may cause stress.

Common maximum temperatures:

• 86°F: Corn, soybeans
• 94°F: Cotton
• No cap: Many cool-season crops

Use Modified GDD when:

• Your crop has a documented maximum temperature
• You're experiencing very hot conditions
• You're following research that specifies MGDD

Standard (Average) Method:

• Simple calculation using daily high and low temperatures
• Good for most agricultural planning
• Works with any weather data

Sine Wave Method:

• More accurate calculation modeling the daily temperature curve
• Better for research and scientific applications
• Requires high-quality min/max temperature data (≥85% complete)

No. You must create a new chart to apply different settings.

Chart settings that cannot be changed after creation include:

• Start date and end date
• Base temperature
• Maximum temperature (Modified GDD)
• Calculation method (Standard vs Sine)

You can create multiple charts for the same location with different settings if you want to compare different configurations.

No. You must create a new location if you want to change weather stations.

Each location is tied to a specific NOAA weather station. If you need to use a different station, create a new location and select the desired weather station during setup.

The Sine method requires high-quality minimum and maximum temperature data. GDD-Pro validates data completeness before allowing Sine calculations.

You cannot enable Sine method if:

• Less than 85% of days have both min and max temperature readings
• Your weather station has significant data gaps
• Recent data hasn't been reported yet

Solution: Use the Standard method instead, which handles missing data by using reported averages, min, and max temperatures. You can try switching to a different nearby weather station with more complete data.

Interpolated data fills gaps when weather stations miss reporting days. GDD-Pro uses linear interpolation to estimate missing temperatures based on surrounding days.

For example, if Monday was 70°F and Wednesday was 74°F, we estimate Tuesday at 72°F.

Your chart displays the number of interpolated days in the summary section. A few interpolated days (5-10) is normal and acceptable. If you see many interpolated days, consider:

• Switching to a more reliable weather station
• Verifying your season dates are correct

Threshold alerts notify you when your GDD accumulation reaches specific milestones:

1. Add a threshold: Set a future GDD value (e.g., 500 GDD for fungicide application)
2. Enable alert: Click the "Standard" alert button or "+ Add Early" for early alerts
3. Automatic checking: GDD-Pro checks daily if thresholds are crossed
4. Email notification: You receive an email when the threshold is reached

Alerts trigger once per threshold. After triggering, the alert status shows "Triggered" and won't send additional emails.

Early notification sends an additional alert before you reach your threshold, giving you advance warning to prepare.

How it works:

• Select an early notification percentage (e.g., 80%, 85%, 90%)
• When GDD reaches that percentage of your threshold, you receive an early alert
• You still receive the standard alert when the full threshold is crossed

Example: With a 500 GDD threshold and 80% early notification:

• At 400 GDD (80%): Early notification email sent
• At 500 GDD (100%): Standard threshold alert sent

This helps you plan operations in advance, especially for time-sensitive activities like spraying or scouting.

Threshold templates are pre-configured sets of GDD milestones for specific crops, making it easy to add multiple thresholds to your chart at once.

Templates include:

• Public templates: System-provided templates for common crops (available to all users)
• Private templates: Your personal templates saved for reuse across multiple charts

Each template contains threshold items with GDD values, names, and notes specific to crop development stages, pest emergence, or management activities.

To apply a template to your chart:

1. Navigate to your chart page
2. In the "Thresholds & Alerts" section, click "Templates"
3. Click the "Search" tab
4. Browse public templates or your private templates
5. Use filters to search by crop, GDD range, or keywords
6. Select individual threshold items or entire templates
7. Click "Add Selected" to apply them to your chart

The thresholds will be copied to your chart and you can then enable alerts or modify them as needed.

No, you cannot directly edit saved templates. To modify a template:

1. Apply the template to a chart first
2. Edit the thresholds directly on your chart
3. Click Templates → Save As to save the modified version as a new template

This workflow preserves your original template while creating an updated version. In future revisions, we may add the ability to edit templates directly from the "My Templates" page.

To create a template:

1. Set up thresholds on a chart the way you want them
2. Click Templates → Save As in the "Thresholds & Alerts" section
3. Enter a template name, crop information, and description
4. Save to your "My Templates" library

Your custom templates can be reused across multiple charts and locations.

Yes. You can generate a shareable link or QR code for your templates:

1. Go to "My Templates" in the navbar
2. Find the template you want to share
3. Click the sharing button to generate a link

Recipients can:

• View the template and all its threshold items (no account required)
• Save a copy to their own account (requires login)

The original template remains in your account. Recipients get their own independent copy.

No. Generating a sharing link does not make your template public or searchable.

Only users who have the specific link will be able to view and save a copy of your template. Your template will not appear in public template searches or be visible to other users unless you share the link with them.

Public Templates:

• System-provided templates for common crops
• Available to all users
• Based on university extension research and agronomic data
• Cannot be edited (but you can copy to and modify on your chart)

Custom Templates (My Templates):

• Created by you for your specific needs
• Only visible to you (unless you share them)
• Can be based on your farm's practices or local recommendations
• Reusable across your charts and locations

Both types work the same way when applying them to charts - they copy the threshold items to your chart where you can enable alerts and make adjustments.

Check these common issues:

1. Spam folder: Check your spam/junk folder for emails from GDD-Pro.com
2. Monthly limit reached: Accounts have notification limits per month
3. Threshold not crossed yet: Check your current GDD vs threshold value

Add comparison seasons directly from your chart page:

1. Look for the "Year Comparisons" section in the left sidebar
2. Select a previous year from the dropdown
3. Click "Add Comparison"
4. The comparison line appears on your chart

Comparisons use the same date range and base temperature as your current chart, showing how previous seasons progressed. You can add multiple years to identify trends and patterns.

Percentile bands show where your current season ranks compared to historical data (Up to 15 years):

• Typical Range (25th-75th percentile): Gray shaded area shows where most seasons fall
• Median Line: Dotted line represents the "average" season (50th percentile)
• Wide Range: Light shaded area shows where 80% of historical seasons accumulated GDD (10th-90th percentile range).

If your current season line is:

• Above typical range: Warmer than normal, ahead of schedule
• Within typical range: Normal season progression
• Below typical range: Cooler than normal, behind schedule

Typical Range (25th-75th percentile):

• Middle 50% of all historical seasons
• What you can "normally" expect
• Useful for typical planning and expectations

Wide Range (10th-90th percentile):

• Captures 80% of all historical seasons
• Excludes the most extreme 10% on each end (coldest/warmest)
• Shows realistic year-to-year variability
• Useful for understanding the expected range without rare outliers

Most seasons stay within the Typical Range. If your current season falls outside the Wide Range, it's in the top or bottom 10% historically—an unusually warm or cold year.

Compare your current season line to the median line (dotted):

• Above the median: Your season is warmer/faster than typical — crops may mature earlier
• On the median: Normal season pace
• Below the median: Your season is cooler/slower than typical — crops may mature later

Enable the percentile bands visualization in the "Season Pace" section of your chart to see this comparison clearly.

GDD-Pro uses weather data from NOAA's Global Historical Climatology Network daily (GHCNd) dataset.

This includes:

• 10,000+ weather stations across North America and globally
• Daily temperature observations (minimum, maximum, average)
• Up to 30 years of historical records for trend analysis
• Quality-controlled, official weather station data

NOAA GHCNd is widely used by agricultural researchers, extension services, and weather applications for its reliability and coverage.

Weather data is updated daily. However, NOAA stations report data with varying delays:

• Most stations: Data available within 1-2 days
• Some stations: May have 2-5 day delays
• Rural stations: Occasionally longer delays

Your chart shows data through the most recent available date. If you don't see yesterday's data yet, it likely hasn't been reported to NOAA. Check back the next day.

GDD-Pro uses established weather data sources (NOAA) and standard calculation methods used by agricultural researchers and extension services.

However, GDD-Pro is currently in beta. We're still validating accuracy across different regions and use cases.

Best practices:

• Use GDD-Pro as one tool in your decision-making process
• Verify critical decisions independently with field scouting
• Consult with agronomists or extension agents for important operations
• Cross-reference with local extension GDD tools when possible

GDD is a helpful guide for timing, but actual field conditions, soil moisture, variety, and other factors also affect crop development.

GDD-Pro offers two sharing options:

1. Image Sharing:

• Click the "Share Image" button on your chart
• Get a shareable link to a static chart image
• Perfect for reports, emails, or presentations
• Recipient doesn't need a GDD-Pro account

2. Interactive Sharing:

• Click the "Interactive Share" button
• Get a link to a live, interactive version of your chart
• Recipient can zoom, pan, and explore data
• No account required to view

Image Sharing:

• Static PNG/JPG image
• Loads quickly, easy to embed
• Good for printed reports or email
• Snapshot of chart at time of sharing

Interactive Sharing:

• Live, interactive chart
• Recipient can hover for data points, zoom, pan
• Better for detailed analysis
• Updates automatically if you update your chart

Choose image sharing for simplicity, interactive sharing when recipients need to explore the data.

During beta, all users have access to the same limits which are listed on the homepage Usage Limits section.

These limits may change as we exit beta. Premium tiers will offer higher limits for users managing multiple farms or conducting extensive research.

If you reach your account limits:

• Locations/Charts: You'll be prompted to delete existing items
• Thresholds: Cannot add more thresholds until you remove existing ones
• Alerts: Cannot enable additional alerts if you're at your active alert limit
• Monthly notifications: Alerts stop triggering until the next month

During beta, if you need higher limits for legitimate use cases, please send us feedback explaining your needs. We'll consider increasing limits or creating a custom plan for your situation.