Adjusting a training week for heat or cold

When weather changes the math

Training plans are written against expected conditions. When the actual week diverges (a 32C heat wave, a sub-zero cold snap), holding pace targets is wrong: either intensity is too hard for the body or the workout becomes a survival drill.

The Hub does not auto-adjust the plan to weather; the coach makes the call. The rules of thumb below help.

Hot week (5C+ above seasonal normal)

What changes

• Aerobic intensity preserved at the same heart rate, NOT the same pace or watts. HR drift is normal.
• Pace and power targets drop by 5 to 10 percent for the same RPE.
• Volume holds or drops 10 percent. Cutting volume hard for one hot week is rarely necessary; cutting intensity is.

What sessions to shift

• Threshold sessions on the bike: move to morning (cooler) or move indoors.
• Threshold sessions running: same. Or replace with HR- capped tempo and accept the slower pace.
• Long sessions: move to early morning. Carry extra fluid and salt. Cool stops planned.

Hydration and fueling

• Fluid per hour +30 to +50 percent vs cool-weather plan.
• Sodium per hour +25 to +40 percent.
• Use the heat as planned heat acclimation (see Pacing the run when it gets hot).

Cold week (5C+ below seasonal normal)

What changes

• Warm-up extended to 20 to 30 minutes.
• High-intensity sessions are usually fine; the body warms up once moving.
• Long aerobic sessions outdoors are fine for fit athletes but injury risk goes up on icy surfaces.

What sessions to shift

• Long outdoor rides are risky on ice. Move to trainer for any ride over 90 minutes if surfaces are unsafe.
• Long runs on safe surfaces only (cleared paths, dry treadmill if needed).

Hydration and fueling

• Cold blunts thirst. Athletes drink less and end up dehydrated. Force fluid every 30 to 45 minutes.
• Cold burns more calories. Bump CHO intake on long sessions by 10 to 15 percent.

What to log

After the week, file:

• Wellness notes about how the athlete responded (sleep, fatigue, soreness).
• Activity notes mentioning conditions if they materially changed the session, especially if pace or power looked off in a way explained by weather.
• For race weeks: an explicit weather note on the race recap under the weather field.

Updating the Hub

• Macrocycle config: no auto-adjust; if the week's plan needs to shift, edit the config_json for that derived plan or re-deploy from the team template with adjusted weekly values.
• Sweat rate test: rerun on a hot day so the fueling planner projections reflect actual sweat rate, not a cool-weather baseline.

See also: Pacing the run when it gets hot, Sweat rate test, Editing a deployed plan.